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AwaSys6 User Manual

1. 1an re Add to batch When starting AwaSys the main window is displayed from which all operations are initiated The main window consists of a menu bar in the top and a toolbar below for quick access to some menu items S Ss 5 Function Toggle connection Show Preferences Calibrate wave gauges Measure paddle gain and delay and create a mechanical transfer file OR Self test to perform a self test of the system setup and to calibrate wave gauges by performing waves as an alternative to above direct calibration toggle fullscreen RI The body of the window is split into four pages 1 Spectral generated signal 2 Replay stored signal 3 4 Batch run Manual signal Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Main window 7 3 1 Spectral generated signal The layout of the spectral generated signal tab differs depending on the setup If AwaSys is setup for 3 D operation some additional input fields appears To start a generation press Start button A replay file can be generated according to selected sea state by right click on the start button and choose Only generate steering signal In this way the steering signal can be inspected before generation if Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 AwaSys Help Document
2. 3 10 Choose Manufacture Choose Data acquisition manufacture H lalla Input DemoDummy Ok Output DemoDummy nd m AwasSys has been developed to support a wide range of I O hardware AwaSys can use different hardware for output paddles and input wave gauges In all cases the DAQ is setup in single shot operation i e timing controlled by AwaSys Contious mode can not be used due to active absorption that has to run in real time The manufactures can either be single value a call to DAQ for reading sending one channel per call or multi value all channels read send with one call per board Below list shows the supported manufacturers and the sampling method For National Instruments where both methods has been implemented it is recommended to use the multi value version DemoDummy simulation x mode National Instuments single value National Instuments multi value C om Port Naples parallel Com Port VTI Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 4 Wave Generation 26 AwaSys Help Document The layout of the wave generation screen differs depending on the setup Below is screen dumps from Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Wave Generation 27 both 2 D and 3 D generation 2 D operation r
3. 52 AwaSys Help Document Timeout ms How long the program will wait for the servo to responds before it reports an error Setting this value to low will not give the servo system enough time to responds No of resend attempts Number of time to resend information if error Naples servo controller only No of Nak attemps Number of times to resend information if information is received but not acknowledged by the other part Naples servo controller only 5 9 Combined Piston Flap Generator Under this item is explained the difference in preferences dialog for dual mode generators compared to single mode generators The dual mode generator available in WaveLab is a combined piston and elevated flap wave maker The rotation point for the elevated flap mode is defined on the wave generator page When defining the rotation point also the voltage clip limits for the flap mode will be defined The voltage clip limits for the piston mode are given in the various table The velocity and acceleration limits are given for piston mode left input field and flap mode right field Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Preferences 53 Look amp feel Additional settings Rs232 Wave Generator Channels Digital Output Operation Main generator settings Generator type combined piston ele v Eiotefion pele 1 hO
4. 1 Saale Baebes 1 1 i 1 1 1 r i 1 jun nenn vot O eae NW Henan o O 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 i 2B 25 24 23 22 214 20 19 18 T7 16 15 mM 13 R2 H 10 9 8 7 6 5 4 3 2 1 0 4 2 Paddle The manual signal page primarily intended for determination of the mechanical transfer constant of the paddles This is done by sending a constant voltage signal to the paddle and measure the stroke from its middle position To avoid sudden movements which could harm the paddle and generate a big damaging wave the signal is changed according to the gain down speed setup in preferences Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 18 AwaSys Help Document 3 7 Calibrate wave gauges ary Calibrate wave Output Number of points Position 1 0 0 Calibration positions Use 0 0 for the SWL and input Position 2 0 1 negative values for decrease in WL probes are moved up and positive for WL increase probes moved down Calib const Zero offset Position 1 Offset mj Position 2 m cab ok Make sure the water is well mixed before calibrating the wave gauges Recalibrate wave gauges if water has changed conductivity Test linearity of wave gauges before using only two points for calibration
5. wanted 2 D operation Replay stored signal F3 any Batch run F4 Ar Manual signal F5 la Spectral generated signal F2 amp Jonswap PM usps JS IMa customs Significant wave height m 0 2 Peak wave period s 2 Peak enhancement constant 33 Model parameters Model Length scale 1 Water depth m 0 5 Sample time 00 20 00 Succeeding Calm down time 23 59 59 Generation method White Noise Absorption InvFFT Random phase Long wave Spectral density m s Spectrum i 4 1 i 1 i i a i i a Signal File Filename test Path Replay File aws CAUsers tla Desktop Wave Gauge File awg E Mod Demand File awd 3 D operation amp Replay stored signal 3 ay Batch run 21 r Manual signal F5 Generation method White Noise InvFFT Random phase v Absorption Long wave la Spectral generated signal F2 Jonswap 2 PM usps JS TMA Customs Significant wave height m 0 2 Peak wave period s 2 Peak enhancement constant 33 Model parameters Model Length scale 1 Water depth m 0 5 Sample time 00 20 00 Succeeding Calm down time 23 59 59 Spectral density Im s rad o o un Spectral density m s I Direction 7 3 D Directional dist
6. Awasys 6 user manual by Palle Meinert Thomas Lykke Andersen Peter Frigaard december 2014 Hydraulic and Coastal Engineering Laboratory Aalborg University Dept of Civil Eng Sohngaardsholmsvej 57 DK9000 Aalborg Denmark Phone 45 99 40 80 80 AwaSys6 Two and three dimensional wave generation by Meinert P Lykke Andersen T and Frigaard P The AwaSys is a wavegeneration program which is capable of generating both 2 D and 3 D waves with active wave absorption systems and simultaneously reflection analysis Two techniques for wave generation are implemented 1 Random phase method 2 White noise filtering method The random phase method is a deterministic method simulating random waves in the frequency domain by assigning random phases to each frequency component Subsequent use of the FFT Algorithm provides the time domain representation of the wave train The white noise filtering method is a non deterministic method which simulate random waves in the time domain by means of digital filtering of white noise Filters are generated in accordance with the specified energy spectrum Non linear interaction between the individual wave components in the wave trains give rise to the so called group bounded long waves which are of second order In both wave synthesis techniques a correct reproduction of the group bounded long waves is possible AwaSys Help Document Copyright Aalborg University Hydra
7. 1 and 1 is maximum groupiness phases 100 correlated i e a freak wave k wave number calculated using linear theory and assumption of constant depth x Distance in meters from the paddle where the waves should be grouped Constant water depth from the paddle to the position is assumed Generate waves using the white noise method Absorb reflected waves Note that this require the absorption parameters and filters under Operation are set correct Correct reproduction of grouped long waves Increase area with correctly generated short crested or oblique long crested waves by using side reflectors Setup side reflector length in preferences Scale of wave parameters according to Froude scaling Note TimeScale SquareRoot LengthScale Prototype water depth Prototype sample time in the format HH MM SS If 00 00 00 is automatic changed to 23 59 59 for generation until user intervention Speed up testing by using absorption to calm down the water surface after the sample time has elapsed Base file name for storing of replay file wave gauge signals and modified demand signals into files The replay file contains data needed for later replay of identical wave trains For more information on the file layout refer to the help for replay The wave gauge file contains the measured surface elevations as used for active absorption and online analysis The modified demand file contains the modified steering signals including mechanical transfer
8. 5 1 5 2 5 3 5 4 5 5 5 6 5 7 5 8 5 9 Operation Wave generator Primary Channels Secondary Channels Digital Output Look amp feel Additional settings Rs232 Combined Piston Flap Generator VN O A N 15 16 17 18 19 20 23 26 32 33 39 43 45 45 47 49 51 52 Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 1 Installing AwaSys AwaSys Help Document Prior to installation of AwaSys the device drivers for the selected data acquisition hardware must be installed Currently hardware from Data Translation National Instruments and Measurement computing are supported as well as RS232 digital communication with two types of servo controllers Running SetupAwaSys exe will start a wizard which will guide through the installation process of Awasys First time AwaSys is run the user will be prompted for the hardware manufacture to use for input and output This question is asked only if the configuration file for AwaSys is not present If the hardware drivers are not installed for the manufacture selected AwaSys will cause an error and terminate Next time AwaSys is executed it will ask again If drivers are installed but no hardware is found AwaSys will ask whether to switch manufacture This can be done seamless if driver and hardware for new manufacture are present Manufacture can be altered later on in th
9. For proper readings and operation the wave gauge signal must always be within the voltage limits of the wave gauge box and data acquisition hardware Therefore it is recommended to have approximately zero volt at SWL The offset voltage at SWL and wave gauge calibration factors should be set up in preferences or measured using this dialog For proper operation the program needs a calibration coefficient for each wave gauge to determine the elevation If the setup allows vertically movement of the wave gauges or alternatively changes in water level this coefficient can also be determined in this dialog The number of points and their positions can be selected in the dialog default two positions with position 2 at 0 1 m corresponding to an increase in WL or downwards movement of gauges of 10 cm from SWL The offset is also determined in calibration procedure but the offset should be remeasured when SWL just slightly changed as it is important to avoid drift of the paddles when using active absorption By clicking Measure position for position 1 the offset is determined without needing to determine calibration constant again AwaSys performs a check on the calibration performed and report result of check in the line Calib OK Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Main window 19 3 8 Measure paddle gain and delay se Recording f 1 2 Hz Inpu
10. The noise can easily be seen in the time series in above figure Despite of this noise active absorption worked well It is possible to check time series of each channel Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Main window 21 by changing the channel to plot in the list which will update entire time series to the selected gauge This is also possible after self test has finished if performance problems are reported for specific gauges Direct calibration of wave gauges using for example the calibrate wave gauges dialog is in many cases not practical especially in basins with many gauges to calibrate In such case a mechanical system is needed to shift gauges automatically for calibration or calibration during filling of the basin is often used However the self calibration might be an alternative which has proven to be accurate at least in cases where significant reflections do occur within the measurement period the 4 waves in the middle Calibration coefficients and offsets determined during the self test can be transferred to the settings on the two tabs Wave Gauge Calibration Coefficients and Wave Gauge Offsets as shown below Here also the current setting and self calibrated values can be seen for all gauges and the deviation The last tab shows wave gauge phase deviation in degrees and milliseconds per gauge as shown in the last picture ste Stopped S
11. active absorption correction clipping and gain up and down The sample frequency of the replay file is communication frequency divided by oversampling factor for irregular waves and the communication frequency for regular and solitary waves The sample frequency of the wave gauge and modified demand files is in all cases the communication sample frequency Description Oblique 2 D waves or irregular 3 D waves Direction of the generated waves 0 degrees is perpendicular to flaps Positive angle is to the left when standing back to the generators Type of spreading function used Choose between cosine distribution Longuet Higgins and normal circular distribution Mathematical expressions given in the spreading functions section Spreading parameter in spreading function i e s in cosine distribution and A in normal circular distribution For more information refer to expressions given in the spreading functions section Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Main window 11 3 2 Standard Spectra Pierson Moskowitz In 1964 W J Pierson and L Moskowitz put forward on the basis of a similarity theory by S A Kitaigorodskii some suggestions for deep water wave spectra for the sea state referred to as fully arisen sea This wave condition refers to the case where the waves have reached an equilibrium state in which energy input from the wind is exactly bal
12. Jonswap generation 00 15 29 00 04 31 un Left Right Paddle movement Im 04 02 0 02 04 Spectral density m s W Original M Modified 7 Absorption v Wave signal Time elapsed 00 15 29 Time remaining Measured Gauge V Predicted for no refl v Spectrum Hm0 0 146m Tp 2 56s Cr 0 1 Frequency Hz N J Tarot Q Actualiv Progress 77 Reflection Generation parameters 4 Jonswap 0 15m Significant wave 2 5s Peak wave period 2 5 Peak enhancement 4 Generation parameters White noise No longwave computat Absorption 1 1 Model length scale 3m Water depth 00 20 00 Generation tin 00 02 00 Calm down tin Path C Users tla Des File test aws Preferences m r 3 D operation Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 28 AwaSys Help Document i _ 2 Jonswap generation 00 18 04 00 01 kla Left Right Average Spectrum v Standard w gradier v Elevation Time Series Gen No 0 Paddle movement i s Im 1 126 1 124 1 122 1 120 1 118 0 1 0 05 0 0 05 041 Generation parameters 4 Jonswap 0 15m Significant wave height 2 5s Peak wave period 3 3 Peak enhancement constant 4 Generation parameters White noise No 2nd order sub harmonics No 2nd order super harmonics o nvuanasnws2nsrnanao BINNER a Dr rf Absorption Comer reflection compensati
13. White noise No longwave computation Absorption 1 1 Model length scale 3m Water depth 00 10 00 Generation time 00 02 00 Calm down time Path C Users tla Desktop File testaws Delete x Clear list E Confirm beginning of each generation Batch run allows to run a batch of wave generations with or without interaction Stored signals can also be queued When adding a new test to the batch list a dialog appears with the possibility of adding a pause before the following test If a solitary wave generation is added to the batch list a dialog asking for the waiting time in final paddle position is also shown Add Pressing this button on the spectral generated signal tab og replay stored signal will add the generation to the batch If pressed while on the Batch run page the page will change to spectral generate signal page for setting up a new entry Delete Deletes selected entries from the batch Clear list Clear the whole list Confirm begging of each generation if checked a dialog will popup between generations to confirm the start of the next run Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Main window 17 3 6 Manual signal Manual signal F5 la Spectral generated signal F2 amp Replay stored signal F3 ay Batch run F4 Ar Channel Volt Meter 12 aS ad
14. amp Coastal Engineering Laboratory All rights reserved 2014 38 AwaSys Help Document Absorption parameters 1 gauge in near field system Field Max number of filter design iterations Cut off wave frequency low Hz Cut off wave frequency high Hz Absorption filter length Amplification coefficient 0 1 View Filter Coefficients Description The maximum number of iterations in the filter design procedure A value of 1 indicate no correction iterations performed a value of 2 means only overall gain and delay adjusted a value higher than two means filter is adjusted in an iterative manner A maximum number of iterations around 30 seems appropriate in most cases The lowest frequency at which the wave absorption system is fully active This low cutoff frequency is necessary to ensure a finite response at low frequencies Response of filter is non zero at 0 Hz meaning that filters will react on a water level change The gain chart shows the gain on 0 Hz typical gain value is five which means a water level drift of 1 cm will mean a generator drift of 5 cm The highest frequency at which the wave absorption system is fully active This cut off frequency is necessary to avoid system to react on noise and be unstable on high frequencies Due to internal computation logic of the program odd filter lengths are required Low frequency response is usually improved with longer filter lengths Fast filter prep
15. generator in AwaSys is found here The optimal ratio of the two modes is automatically used in generation and in 2 gauge in far field active absorption system For 1 gauge active absorption system piston mode is always used for the absorption correction In case of Elevated Piston Combined and Elevated Hinge paddle types vertical position should be stated A list of standard position can be maintained by using the add new position entry to create one and delete button to erase current position The time used for gaining up and down when the wave generation starts and stops Determine how fast paddle s are allowed the move when using the manual control feature or gaining down to from initial and zero position for example if generation is stopped using quick stop To protect the wave generation system the maximum allowed velocity of the paddles during generation can be set according to the design of the generators For hinged and combined mode paddles the value is specified for the same level as the transfer constant Generating waves where this limit is often exceeded in the original signal is not recommended as it will lead to decreased wave generation and absorption performance due to clipping modifications To protect the wave generation system the maximum allowed acceleration of the paddles during generation can be set according to the design of the generators For hinged and combined mode paddles the value is specified for the sa
16. method is two gauges in far filed two channels per generator is needed only recommended in 2 D If active absorption is one gauge in the near filed one channel per generator is needed The gauges need to follow the same order as the paddle channels i e first channels for paddle 0 then channels for paddle 1 and so on If number of gauges is a multiplum of above given required channel numbers then signals are averaged useful in 2 D to minimize influence of noise and cross modes In this case gauges that are averaged must follow each other in the list See above example for 2 D operation 1 generator and active absorption based on two gauges in the far filed In this example is used average of first three as signal one and average of last three as signal 2 in the absorption compensation Will automatic setup the stated number of channels using default values from the Wave generator page Data acquisition board number Channel number on the board The wave gauge X coordinate This is the perpendicular distance from the paddle s and is used for absorption Offset value from calibrating the wave gauges This value can be detected using the Calibrate wave gauges dialog or the self test dialog Calibration coefficient from calibrating the wavegauges This value can be detected using the Calibrate wave gauges dialog or the self test dialog Gain code for the data acquisition input channel Please refer to the manual of the data acquisition for
17. the gain of first frequency to unity If this option is used it is important that the starting frequency is sufficiently low Filter delay Measuring the delay of a filter is done in the same way as measurement of the servo delay However with a few differences The output of the filter should be connected to input channel 2 same as wave gauge 2 and there is usually no need to go through several frequencies as delay is usually independent on frequency Input Field Description Sample frequency Hz Sample frequency at which the measurements are performed Amplitude Volt Amplitude of the sinus signal Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 20 AwaSys Help Document 3 9 Wave frequency range Hz Interval step size Hz Number of iterations Result Field Set constant servo delay Set gauge filter delay Set mechanical transfer file Start and end frequency for the measurement Measurement can be aborted at any time without loosing any measurement results The frequency step size This determine how detailed in the frequency domain the measurement will be If set higher than 1 the program will repeat the measurements utilizing the new gain Description Include the servo delay in the constant delay Include the filter delay in the constant delay Set preferences to use the mechanical transfer file created Self Test lt 2 St
18. 0 90m Vmin Tapering time s 10 Gain down speed m s 0 02 Max paddle velocity m s 2 6 Max paddle acceleration m s 5 5 Spectrum low cut off freq factor 0 333 Spectrum high cut off freq factor 10 Spectrum low cut off freq Hz 0 05 a Spectrum high cut off freq Hz 3 3 D mode generator settings Flap width m 0 5 Max neighbour pos difference m Length of side reflectors m 2 3 Angle width degrees 60 3D Flap type Box 3 D reverse piston order E Various Ke Value Sensitive operation False Warning time s 1 Min input voltage v 10 Max input voltage v 10 Min output voltage v 10 Max output voltage v 10 Paddle offset voltage v 0 Paddle initial voltage v 0 Default gain code input 1 Default gain code output 1 Differential Input True The two modes are independent and controlled by a control signal for each mode per generator The Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 AwaSys Help Document channels need to be defined in the order Ch 0 Control signal for piston 1 Ch 1 Control signal for flap 1 Ch 2 Control signal for piston 2 Ch 3 Control signal for flap 2 and so forth Below show and example of a flume channel configuration with a dual mode generator Digital Output Look amp feel Additional settings Rs232 Operation Wawe Generator Ch
19. 000 0 000 1 0000 1 U 0 6 000 0 000 1 0 1 0 000 0 000 1 0000 1 1 0 1 6 000 0 000 2 0 2 0 000 0 000 1 0000 1 2 0 2 6 000 0 000 3 0 3 0 000 0 000 1 0000 1 3 0 3 6 600 0 000 4 0 4 0 000 0 000 1 0000 1 4 0 4 6 600 0 000 0 5 0 000 0 000 1 0000 1 5 0 5 6 600 0 000 Paddles Paddles Number of paddle channels 64 Number ofpaddle channels 1 Default Transfer constant m volt 0 1 Default Transfer constant m volt 0 1 Auto populate channels Auto populate channels Disabl No Daqg Brd Daq Ch Transt C 0 1 1 0 E 0 0 0 0 1 0 1 1 0 0 1 1 0 0 1 1 0 bal Position feedback 2 D Position feedback 2 D Board Channel Gain coeff Offset Board Channel Gain coeff Nolink Nolink 1 000 0 000 Nolink Nolink 1000 f On this page the number of channels to use for input and output is set up Correct number of wave gauges see below under number of gauges will enable active absorption and the dialog will be Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 44 AwaSys Help Document extended with absorption filter charts see absorption under Operation Wave gauges Field Number of gauges Auto populate channels Brd Ch X Offset Calib Gain Paddles Field Number of paddle channels Auto populate channels Daq Brd Daq Ch Transf C Gain code Position feedback 2 D Description The number of wave gauges If active absorption
20. 1 5 8 Rs232 Two manufacturer are supported for com port RS232 communication with servo controller Below pictures show the RS232 tab when Naples is selected The VTI servo controller uses a send and forget protocol i e samples that are incorrect received is not retransmitted Naples servo controller uses a protocol with handshaking i e samples that are incorrect received will be resend for a given number of attempts Operation Wave Generator Channels Look amp feel Additional setings Rs232 Servo setup Port name Boardnumber D 1 2 4 m Baud rate 119200 Flow control Hardware 10 m Channels per port Timeout ms o w No ofresend attempts 3 No of Nak attemps 3 Note When using Rs232 communication the program makes following assumption to make it fit into its structure 1 olt 1000 Servo positions All Rs232 ports are treated as Dag boards The first port is named 0 second is 1 etc This tab is only present if output manufacture is set to Rs232 At the top is listet the availible ports and their corresponding board name Field Description Baud rate The communication speed of the serial port Flow control none software hardware Channels per port The number of pistons controlled by each port Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014
21. The lowest frequency at which the wave absorption system is fully active This low cutoff frequency is necessary to ensure a finite response at low frequencies to avoid significant drift of the paddles Cut off wave frequency high Hz The highest frequency at which the wave absorption system is fully active This cut off frequency is necessary to avoid system to react on noise and to avoid the singularity due to the spacing between the two wave gauges Absorption filter length The filter length of the absorption filter s Due to internal computation logic of the program odd filter lengths are required To obtain the best possible fit of the filters a long filter is desired Fast filter preparation for the filter lengths 563 1013 1823 3281 Adjust the filter length to obtain the best reflection coefficient curve value of zero within the cut off frequencies Amplification coefficient 0 1 Can be set to any real value between 0 and 1 The amplification coefficient defines the efficiency of the active absorption system 1 is always recommend for this absorption system View Filter Coefficients Can be used to view the filter coefficients of the two filters The filter coefficients at time zero should approach zero If not there are different solutions to improve performance 1 position gauges further away from the generator 2 decrease filter length 3 increase cut off frequency low Copyright Aalborg University Hydraulic
22. Windows Update gt Change settings gt Turn off Automatic Update Checking check manually when AwasSys is not running Ensure Windows Defender is not set to run automatically e Disable the Indexing Service Windows Search Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 3 Main window AwaSys Help Document File Edit Run Setup Help EAR ance Spectral generated signal F2 TMA x EM MBM EM Js IMA ERF Custon Significant wave height Hm0 m 0 1 Peak wave period s 2 Peak enhancement constant 33 Model parameters Model Length scale 1 Water depth m 0 7 gt Fee TR 80 60 40 20 0 20 40 60 ern h j teta degree i 00 10 00 Sample time M over M tf 0 75 S di Im down ti 00 00 00 os 1 15 2 fip 10 7 fip 15 ucceeaing calm down time Hz Generation method s Absorption a White Noise a P 3D waves irregular v Direction 20 2 Comer Reflection amp InvFFT Random phase 2nd order sub harmonics Cosine 2s frequency dependent gt Spreading 10 2nd order super harmonics Output Signal File Random seed value 0 randomize 1 Filename DalrympleNewCorner Amout of Wave Groupiness 0 1 x 1 0 Path CAUsersitla Desktop Replay File aws Wave Gauge File awg Mod Demand F
23. anced by energy loss The equilibrium form of the Pierson Moskowitz spectrum for fully developed seas may be expressed in terms of wave frequency f and wind speed at 19 5m above mean sea level U19 5 as a f S f 9 expl 0 74 2 1 2x fj where 0 0081 fo g 2 U19 5 The Pierson Moskowitz spectrum describes a fully developed sea with one parameter the wind speed and assumes that both the fetch and duration are infinite This idealization is justified when wind blows over a large area at a constant speed without substantial change in direction for tens of hours Pierson Moskowitz parameterised ITTC 81 spectrum The Pierson Moskowitz spectrum is transformed to a parameterised spectrum by Hmo 4 Mo 2 T 14 T 14 3 m The parameterised spectrum is given by re N4 ee r 5 ffp 4 S f zg Hmo fp f l 7 T 4 JONSWAP The Joint North Sea Wave Project JONSWAP was started in 1967 as a collaboration among institutes in Germany Holland UK and USA The objectives of the project was originally partly to investigate the growth of waves under fetch limited condition and partly to investigate wave transformation from sea to shallow water area Simultaneous measurements of waves and winds were taken at stations along a line extending 160 km in a westerly direction from the island of Sylt in the Germany Bright During the processing of a large number of spectra corresponding to steady easterly wind t
24. and delays j Absorption Method 1 gauge in near field Absorption parameters Max number of filter design iterations 50 Cut off wave frequency low Hz 0 1 Cut off wave frequency high Hz 1 Sie 01 02 03 04 05 06 07 08 09 1 11 12 13 14 15 16 17 18 19 Frequency Hz Preview absorptionfilter ___ View fiter coefficients Ddeg 20 deg 40 deg 60 deg 80 deg Absorption filter length 3281 1 w am Amplification coefficient 0 1 2 gauges far field Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Preferences Wave Generator Digital Output Absorption filter preview Look amp Feel Additional Settings Operation Primary Channels Secondary Channels Xg Model setup parameters Max depth of facility wall height m Actual water depth in facility m Sampling parameters Sample frequency Hz Timer type Paddle response fine tuning Constant delay s Mechanical transfer file 45 1 2 50 Int multimedia v RR zu SCHEIN SS 222 SS RR FIT DIR RE X Phase angle deg 3 02040608 1 12 Frequency Hz 0 02 04 06 08 1 1214 16 18 Frequency Hz Theoretical Actual Measure gain and delays Absorption Method Absorption parameters Cut off wave frequency low Hz Cut off wave frequency high Hz A
25. annels Wave gauges Number of gauges 2 Auto populate channels 6 000 3 897 0 117 1 6 600 3 69 0 117 1 Paddles Number ofpaddle channels 2 Default Transfer constant m volt 0 1 Auto populate channels No Daqg Brd Dag Ch Transf C Gain cod 0 0 2 1 1 0 065 1 Position feedback 2 D Board Channel Gain coeff Offset 0 63 z 2 334 The mechanical transfer file should include five columns i e 1 frequency 2 gain for piston mode 3 Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Preferences 55 phase shift for piston mode 4 gain for flap mode and 5 phase shift for flap mode For 1 gauge in the near filed active absorption system the absorption is made in pure piston mode and is similar to that described for single mode generators For 2 gauges in the far field active absorption system the lowest frequencies are absorbed with piston mode and the highest frequencies with flap mode In between a combination of the two is used see example of gain on the two modes on below figure The same distribution in the two modes is used for the generation and is chosen to minimize the near field effects For further information refer to the technical documentation Digital Output Look amp feel Additional settings Ps232 Operation Wave Generator Channels Model setup pa
26. aration for the filter lengths 563 1013 1823 3281 Can be set to any real value between 0 and 1 The amplification coefficient defines the efficiency of the active absorption system A value lower than one can be used to improve filter stability if needed If there are frequencies where the reflection coefficient is significantly above one it is recommended to reduce the amplification coefficient in order to improve stability of the system Can be used to view the filter coefficients of the filter The filter coefficients at the left end of the filter should approach zero otherwise filter is too short Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Preferences 5 2 Wave generator Operation Secondary Channels Look amp Feel Additional Settings RS232 Wave Generator Digital Output piston Main generator settings Generator type x Elevation position 1 hO 1 50m Ymin Tapering time s 10 Gain down speed m s 0 02 Max paddle velocity m s Max paddle acceleration m s Spectrum low cut off freq factor Spectrum high cut off freq factor Spectrum low cut off freq Hz Spectrum high cut off freq Hz 3 D mode generator settings Flap width m 0 5 Max neighbour pos difference m 0 3 Length of side reflectors rn 3 Angle width degrees 60 3D Flap type Vertical hinged r 3 D rever
27. bsorption filter length Amplification coefficient 0 1 2 gauges in far field v 1 gt gt gt ee Phase angle deg SAAT Paddle reflection coefficient I 02040608 1 12 14 1618 2 Frequency Hz at Preview absorption filter View filter coefficients 002040608 1 12141618 2 Theoretical Actual Frequency Hz Ok Cancel This page contains parameters for model setup sampling and absorption This is the parameters most likely to change between test setups Model setup parameters Field Max depth of facility wall height m Actual water depth in facility m Sampling parameters Field Sample Frequency Hz Timer type Description Physical height of the flume used for validation of generation parameters Water depth at the location of the paddle the wave gauge s used for absorption If absorption method is two gauges in far field and the flume bottom is slightly inclined an average water depth from the generator to the gauges should be used Description The frequency by which elevation is measured by the wave gauges and control signal is send to the servo A high sample frequency is needed to have smooth operation However a high sample frequency can reduce the spectral resolution of the generation and on line analysis To compensate for this it can be necessary to increase some of the filter lengths used during computation or the ov
28. e generator using the Measure paddle gain and delay dialog Field Board Description Data acquisition board number Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Preferences 45 5 4 5 5 Channel Channel number on the board Gain coeff Gain coefficient The relation between the output signal and the feedback signal of the servo controller see below figure If connected directly to the output channel Gain coefficient 1 Note that the raw servo feedback signal has in many cases opposite sign of the send signal i e gain coef should be negative Offset A possible offset between the output signal and the feedback signal from the servo controller see below figure If connected directly to the output channel offset 0 Below picture shows an example of determination of feedback gain coefficient and offset In this example gain coeff 2 334 and offset 4 673 V Demand Signal V Feedback Signal V Secondary Channels Secondary channels can be used for two options 1 Additional wave generator channels that work as active absorption only active rear end absorber Wave generation direction can either be from primary towards secondary or opposite set in operation tab 2 Additional input channels to sample and store in awg file no secondary paddle channels to be defined The settings of the secondary channels a
29. e program by holding SHIFT key down when starting the program To uninstall AwaSys select the uninstall menu item in start menu or use add remove programs in control panel Only program files are removed settings and previous parameters will not be deleted The calibration procedure of the wave generation involves 1 Setup general parameters in preferences like generator type etc 2 Determination of transfer constant for paddle This can be done from manual signal by sending out different voltage levels and measure corresponding movements Calibration of feedback signal see documentation for Preferences dialog Determine mechanical frequency response using measure gain and delay dialog Configuration of wave gauge setup distance to paddle and calibration of gauges Self Test of system setup Optimization of absorption filters for different water depths Test of generated 2 D waves regular and irregular for low and high reflective conditions and different sea states Test of generated 3 D waves for low and high reflective conditions and different sea states ONOORW co Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 2 Optimal PC configuration for AwaSys AwaSys Help Document The standard configuration of most PCs will work fine with AwaSys However increased timing accuracy can be archived by following the recommendations given here Se
30. eering Laboratory All rights reserved 2014 48 AwaSys Help Document Distance increment on axes m Style Field Resize components equally Generation view style Generation view colour style Custom colours paddle history charts If this value is exceeded during generation the charts will automatically adjust Increment value of distance axes Description If checked the individual panels of a window will their size ratio on re size of the window The layout of the generation window can be changed to fit the orientation of the flume A few colour schemes for the charts Only visible when custom colours is selected as colour style Here each component can be assigned a custom colour Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Preferences 5 7 Additional settings Wave Generator Digital Output Operation Primary Channels Secondary Channels Look amp Feel Change Additional settings Addition settings Additional Settings Ke Value Gauge calibration freq Hz Gauge calibration samples 400 Gauge calibration distance m 0 100 Gauge zero volt elev above floor m 0 020 Preview absorp max freq Hz 4 Preview spectra points 100 Preview specra max freq Hz 3 show paddle movement True Show elevation history True Show paddle history True Show on line analysis True Show generation info T
31. elf Test Parameters Main Results Wave Gauge Calibration Coefficients Wave Gauge Offsets Wave Gauge Phases Water depth at generator m 0 48 Gauge No Settings Value m v Measured Value m Deviation Wave height m i 1 0 059 0 1 Wave period s Start Self Test Update Calibration Coefficients to Self Test Values Time s MV Target Elevation Measured Elevation Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 22 AwaSys Help Document Awe Stopped Self Test Parameters Main Results Wave Gauge Calibration Coefficients Wave Gauge Offsets Wave Gauge Phases Water depth at generator m 10 48 Gauge No Settings Value V Measured Value v Deviation mm Wave height m 0 0 A 0 365 0 7 Wave period s Start Self Test Update Offsets to Self Test Values VW Target Elevation V Measured Elevation 6 Stopped Self Test Parameters Main Results Wave Gauge Calibration Coefficients Wave Gauge Offsets Wave Gauge Phases Water depth at generator m 0 48 Gauge No Phase Deviation dq Delay Deviation m Wave height m 0 028 Hi 8 Wawe period s 1 39 Start Self Test V Target Elevation V Measured Elevation Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Main window 23
32. enerators The 3 D absorption performance curve will also depend on the flap type Moreover it changes the visualization of the paddles Uncheck for normal piston order and check for reverse piston order Normal piston order is numbering from left to right when standing in front of the generators with face to the generators Reverse piston order is opposite Description Set this setting to true if the wave generation is easily affected by user interaction This has detected on systems using old ISA bus acquisition cards This switch will cause the program to start in full screen and here by make it more difficult to start working in other programs Further more the only enabled control during wave generation is the stop buttons Setting this options gt zero display a warning every time the program will connect to the servo controller This is to prevent any sudden movement Setting a time larger than zero will cause the dialog to blocked for this time forcing the operator to notice the warning Setting a negative value will not display the warning The minimum input voltage to be expected from wave gauges and feed back channel The maximum input voltage to be expected from wave gauges and feed back channel The minimum of the output range Signal is clipped if this value is exceeded to avoid wrecking the wave generator The maximum of the output range Signal is clipped if this value is exceeded to avoid wrecking the wave generator At
33. er sampling factor see Additional settings Ext data acq timer Int Multimedia Int high perf count External data acq It should guaranty high accuracy by using a clock on the data acquisition card to trigger action Was considered but never implemented Internal Multimedia timer is a special kind of high precision timer offered by Microsoft Windows Since intervals can only be set in milliseconds not all Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 36 AwaSys Help Document frequencies are supported Only frequencies which can be divided into 1000 without remainder are possible Internal High performance counter Most pc s are equipped with a high performance counter which is a hardware generated very fast and precise counter By checking this counter and constantly adjusting the timer interval all frequencies can be simulated It is recommended to use the Multimedia timer for optimum results Only if a specific non multimedia timer frequency is demanded should internal high performance counter timer be selected Paddle response fine tuning Field Description Constant delay s The delay from a signal is sent to the servo controller until the piston move usually 35 ms for VTI controller This information is needed to optimize functionality of absorption If the signal from the wave gauges is send through a filter the filter delay shou
34. f f expl 1 03 9 where 0 257 fp 1 Ts Modified Bretschneider Mitsuyasi The modified Bretschenieder Mitsuyasi spectrum uses H 0 915 H no and a modified factor in the exponential function fe 4 S f o H2 f f exp 0 75 2 10 where 0 205 fp 1 Ts TMA The TMA spectrum is developed for finite water depth where the frequency scaling is different from the Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Main window 13 3 3 above given spectra which does not depend on depth In effect the TMA spectrum change the decay of the spectral function of the high frequency side from f to f3 in shallow waters by multiplication of JONSWAP spectrum with weighing factor as derived by Kitaigorodskii et al 1975 This gives a wider spectrum in shallow waters compared to the JONSWAP spectrum Its validity is verified by measurements from TEXEL in the North Sea MARSEN project in the North Sea and ARSLOE project in Duck North Carolina Here from comes the name of the spectrum Fz co hea as 1 2a R a Doh 1 Ro sin 202R o D a Neinite R o tanh R 1 Spreading functions Cosine 2s distribution Longuet Higgins Dif 2 T s 1 6 8 f m I 2s 1 2 The spreading parameter s can be taken as a constant frequency independent or as frequency dependent Prototype measurements sh
35. field Goda and Suzuki 1979 is used while Schaffer and Hyllested 2000 is used for one gauge in the near field For later documentation the spectrum and estimated wave characteristics can be printed or exported This is done through the pop up menu which appears by right click on the chart Paddle movement and paddle movement history The movement of the paddle s can be monitored real time for original signal unclipped and without absorption correction and modified including clipping and active absorption For 2 D operation the time history of the original and modified paddle position signal is also shown Status bar The status bar shows information on elapsed and remaining time the buffer status of calculated new samples the fraction of sample where clipping has been made Clipping is made due to stroke limits velocity and acceleration limits termed 2 D clipping maximum displacement between paddles termed 3 D clipping If clipping has occurred during the test a warning is showed after the test has finished with information on the number of samples modified due to 2 D and 3 D clipping respectively Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 5 Preferences 32 AwaSys Help Document The behaviour of AwaSys is configured in preferences Settings in preferences are divided into user settings and facility settings An administrator password can be set wi
36. generators Y axis is the wave generation line Generate spectra using the random phase method The random phase generation method is a deterministic method and to obtain a better a statistically distribution of the waves and avoid repetition of the same waves during a wave series modification of some parameters under preferences may be required The parameters in question are Inverse FFT length and Oversampling factor under Additional settings When generating with random phase the same series of waves can be repeated by setting a random seed value If random seed value is set to 0 randomize is performed to set the seed value Randomize sets uses a algorithm to set the seed value from the current value of the computers internal clock A wave group is generally defined as a sequence of waves In AwasSys different amount of wave groupiness can be generated Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 10 AwaSys Help Document White noise Absorption Long waves computation Corner Reflection Model length scale Water depth Sample time Succeeding calm down time Signal file Additonal 3 D parameters Field 3 D type Direction degrees Spreading distribution Spreading by correlating phases x according to the formula 9 C 9 1 C random k x where C coefficient between 0 and 1 where 0 is normal groupiness phases uncorrelated GF
37. he so called JONSWAP spectrum was obtained f 4 yb 5 i 2 a g 5 S f f exp f a P 7 where a 0 076 g F U3 _35 g g F u2 j 2 f J f s Un E F B exy 2 0 f Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 12 AwaSys Help Document 0 07 for f lt f 10 09 for f gt f The JONSWAP spectrum is characterized by a parameter the so called peak enhancement parameter which controls the sharpness of the spectral peak In the North Sea the peak enhancement coefficient ranges from 1 to 7 with an average value of 3 3 JONSWAP parameterised The parameterised JONSWAP spectrum reads fe 4 5 fp S f H2g 14 1 exp 2 e y 6 a f where 0 0624 Q 0 230 0 0336 y ae 7 B exp Eh 2 2 20 0 07 for f lt f 10 09 for f gt f The JONSWAP spectrum is characterized by a parameter the so called peak enhancement parameter which controls the sharpness of the spectral peak In the North Sea the peak enhancement coefficient ranges from 1 to 7 with an average value of 3 3 Bretschneider ISSC spectrum This was developed for the North Atlantic unidirectional seas with infinite depth no swell and unlimited fetch 7 f 4 Suhl ff f exp 1 25 8 where 1 25 4 Bretschneider Mitsuyasi fe 4 S f a H2
38. ity Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Preferences 37 reflection coefficient would equal 100 For the system based on gauges on the paddle faces the reflection will be shown also for reflections approaching obliquely the generator The absorption performance for highly oblique components can be increased by lowering the amplification coefficient leading to a wide range of frequencies and directions with very low coefficient of reflection This lower amplification coefficient will also improve the stability of the system When setting the absorption parameters the goal is to find filter parameters which yields a reflection coefficient as close to zero within the desired area of application and without instability issues Areas with reflection coefficient significant higher than unity are possible instability areas and should thus be avoided by proper absorption parameters The charts are automatically updated if any of the involving parameters are changes Operation page e Water depth in flume e Sample frequency e Servo delay e Mechanical transfer file e Cut off wave frequency low e Cut off wave frequency high e Absorption filter length e Amplification coefficient Channels page e Dist from paddle of wave gauges Wave Generator page e Generator Type e Elevation position Absorption parameters 2 gauges in far field system Field Description Cut off wave frequency low Hz
39. ive operation warning time s Min input voltage Max input voltage Min output voltage Max output voltage Paddle offset voltage Paddle initial voltage Default gain code input Default Output gain code generators 3 D operation only Should be used to prevent gaps when generators are not in snake principle and to prevent paddles to be removed if generators are in snake principle operation Will also limit displacements between locked transfer constant of zero and normal operating generators For hinged and combined generators the value refer to the level at which the transfer constant is given The length of the side reflectors used for corner reflection compensation to increase area with correctly generated waves It is recommended to have the first part near the generator as reflective and the last part with some absorption For reflective side walls etending beyound the main testing area set instead the distance from the wavemaker to the main testing area The maximum wave angle which can be generated 3 D operation only Setting it too high will cause creation of high spurious waves setting it low will not make full use of the of the wave generator potential Generator face type i e boxes piecewise constant or vertical hinged piecewise linear Used for spurious wave correction as vertical hinged paddles have increased generation possibilities frequency direction combinations compared to box mode g
40. ld also be accounted here Mechanical transfer file File name of a text file which contains information about the phase and gain of some discrete frequencies The file can be created by using the generation mechanical transfer file dialog See Measure gain and delay below The file should contain three columns Frequency Hz Gain and Phase radians If a mechanical transfer file is used together with a constant servo delay the phase and delay are added The mechanical transfer file should include three columns i e 1 frequency 2 gain and 3 phase shift Measure gain and delay Brings up the Measure paddle gain and delay dialog Absorption parameters general Two absorption methods are implemented and chosen between here 1 System based on Frigaard and Brorsen 1995 method The system uses two wave gauges in the far field to sperate into incident and reflected waves in real time by means of digital FIR filters In essence the calculation of the paddle displacement correction signal needed for absorption of the reflected waves is determined by digital filtering and subsequent superposition of the two filtered surface elevation signals This method can be used for 2 D situations only In this system the online analysis is based on the principle of Goda and Suzuki 1979 and provides updated information about the actual generated wave s incident to the test structure 2 System based on Milgram 1970 Schaffer and Jakobsen 2003 a
41. m are needed Field Spectra Wave height m Wave period s Significant wave height m Significant wave period s Wind speed m s Peak wave period s Peak enhancement constant Custom spectrum file Custom time series file File Sample Frequency Hz X coordinate for reproduction m Y coordinate for reproduction m Random phase Random seed value Amount of Wave Groupiness Description Type of waves to generate for more information see here Depending on this selection only the relevant input field are shown Prototype wave height for regular waves Prototype wave period for regular waves Prototype significant wave height Hm0 Prototype significant wave period Prototype wind speed Prototype peak wave period Peak enhancement constant Text file with lines of Frequency Hz and Spectral density m s separated by space or tab Text file with lines of surface elevations m Sample frequency of surface elevation tie series for custom time series reproduction X coordinate to reproduce custom time series surface elevations Linear theory and constant depth assumed X Y origin is at the right hand basin side and paddle mean position X axis is perpendicular to generators Y coordinate to reproduce custom time series surface elevations Linear theory and constant depth assumed X Y origin is at the right hand basin side and paddle mean position Right hand basin side is defined when standing back to
42. me level as the transfer constant Especially electrical motors can impose some restrictions on the accelerations Generating waves where this limit is often exceeded in the original signal is not recommended as it will lead to decreased wave generation and absorption performance due to clipping modifications Spectra low bound cut off is at a frequency of peak frequency times this factor Is included to prevent seiches in the facility and to prevent large paddle drift due to low frequencies Energy in spectrum will be kept by scaling spectrum Spectra high bound cut off is at a frequency of peak frequency times this factor Energy in spectrum will be kept by scaling spectrum Spectra low bound cut off at fixed frequency Energy in spectrum will be kept by scaling spectrum Spectra high bound cut off at fixed frequency Can be set lower than default value if generators do not respond well to high frequency components Energy in spectrum will be kept by scaling spectrum Width of each flap 8 D operation only If snake principle is used the first and last paddle should be half the width of the number given here Maximum displacement difference between neighbouring Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 42 AwaSys Help Document Length of side reflectors m Angle width degrees 3D Flap Type 3D reverse piston order Various Field Sensit
43. n The generation is not abrupt stopped but is slowly gained down in order not to damage generators Quick stop can be used as emergency stop and stops abrupt Generation parameters This panel show a summary of the generation parameters Elevation This chart displays the history of measured elevations by the wave gauges Toggle between wave gauge s to show in list in upper right corner Two gauge signals are shown in case of active absorption based on two gauges in the far filed In case of active absorption based on one gauge in the near field is shown measured elevation predicted elevation for no reflection The difference between the two is the signal that goes trough the filter This signal is termed reflection but include also Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Wave Generation 29 near field from active absorption signal and re reflections Real time analysis This panel provide information about the actual generated wave field The target spectrum and measured incident wave spectra are shown and the reflection coefficient as function of frequency is shown In the caption is shown estimated wave height period and total reflection coefficient The estimated incident wave characteristics are updated and averaged over the total run time The method used for online analysis depend on the active absorption method chosen In case of two gauges in the far
44. nd others The system uses one wave gauge on the paddle front to determine deviation from generated near field waves This deviation signal is send to a digital filter leading to a paddle correction signal The method here is not based on a direct separation into incident and reflected waves but relay on the generated near field only Therefore accurate calibration is very important otherwise significant false reflections might be detected The advantage of the system is that it has better performance for long waves and can be applied in 3 D situations In this system the online analysis is based on the principle of Schaffer and Hyllested 2000 and provides updated information about the actual generated wave s incident to the test structure Absorption is possible if correct number of input channels have been defined under channels according to the absorption method selected in that case the preferences dialog is extended with charts helping to setup the optimum absorption filter parameters The phase shift chart s and gain chart show a comparison between the theoretical phase shift and actual phase shift and gain realized by the filter s Phase shift and amplification combined is shown on the last chart and is named the Paddle reflection coefficient It gives the coefficient of reflection as function of frequency In case of 100 absorption the reflection coefficient equals zero while incase of no active absorption the Copyright Aalborg Univers
45. ok amp feel Additional settings Rs232 Servo Controller Gain Up Gain up time s 5 Select manufacturer input or output NI amp DT supported Input DAQ manufacturer Board Line 0 zj 0 4 Test Beginning Syncronization Select manufacturer input or output NI amp DT supported Input DAQ manufacturer X Board Line 0 zj 2 Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Preferences 47 5 6 Look amp feel Operation Wave Generator Channels Digital Output Look amp feel Additional settings Rs232 Wave generation chart axes Time period shown on graphs s 25 Time increment on axes s 2 Min max stroke elevation m 0 05 Distance increment on axes m 0 05 Style Resize components equally v Generation view style Left to right z Generation view colour style Standard w gradient v Settings on this page are all related to the behaviour and cosmetic of the program Wave generation chart axes Field _ Description Time period shown on graphs s History length in seconds of measured elevation and paddle movement Time increment on axes s Increment value of time axes Min max stroke elevation m Initial minimum and maximum of length axis on the elevation and Copyright Aalborg University Hydraulic amp Coastal Engin
46. olumns per generator includes signals used for the one gauge active absorption system for absorption signal computations and for online analysis The second column is the near field surface elevation on the location of the surface elevation probe used given in metre The third column is the far field surface elevation at the paddle i e excluding evanescent modes used for online analysis only given in metre In case active absorption system is not selected to one gauge system or wave gauges not correctly defined these two last columns per generator will contain zeroes For compatibility reasons with older AwaSys versions it is included an option to choose file format just below the generation information tree view in the right hand side of the window AwaSys versions 4 0 5 5 uses only a single column per generator namely the steering signal AwaSys 6 beta used two channels per generator Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 16 AwaSys Help Document 3 5 Batch run lm Spectral generated signal 2 amp Replay stored signal F3 By Batch run F4 Ay Manual signal F5 Generation information No Spectrum Wave height Period Time Specific par 1 Jonswap 0 10 2 50 00 10 00 4 Jonswap f prey a ih seq Ts 0 15m Significant wawe height isesi Spana a ILMENAU 2 55 Peak wave period 2 5 Peak enhancement constant 4 Generation parameters
47. on Average Spectrum 3 D Directional distribution 1 1 Model length scale 3 3m Water depth Hm 0 147m Ths 2498 Cr 0 0 00 20 00 Generation time 1 20 i 0 01 1 B Leone ee 2 00 02 00 Calm down time 0 008 08 gt 4 3 D parameters 3 D waves irregular 2 0 0064 068 Ir 3 0 degrees Mean direction 0 004 4 04 a Cosine spreading distribution Bon Te ee a en 0 2 3 10 spreading parameter Preferences 0 0 5 15 2 1 Frequency Hz IV Pb arosi O Actua 60 40 20 0 20 40 6 teta degree V Absorption v Wave signal Quick stop esc Soft stop Time elapsed 00 18 46 Time remaining 00 01 14 Buffer Fine Signal clipping 0 0 o Progress 93 Plot Channel 3 D only In the upper right hand corner the user can choose the generator number to show in online monitoring Average will show average spectrum from all generators and surface elevation time series from generator number zero Toggle signals Absorption and wave signal can be toggled on off during generation using the check boxes in the lower left corner of the window This is especially useful when testing the absorption settings Stopping and calm down When the desired generation time has elapsed the generation automatically stops If absorption was selected on start AwaSys will continue to absorp for the stated calm down period A test series can be aborted before time by pressing the soft stop butto
48. opped Self Test Parameters Main Results Wawe Gauge Calibration Coefficients Wave Gauge Offsets Wave G K Self Test Not Passed Water depth at generator m 0 48 Wave height m 0 028 Deviation 0 00452 Wave period s 1 39 Settings Measured Start Self Test Clock pace Feedback noise level 1 9 Mechanical delay ms 1m 117 Transfer constant incl mech gain m v 0 088 0 088 Wave gauge noise level max value 7 2 Wave gauge calib max error Wave gauge offset max error mm Wave gauge phase max error Time s M Target Elevation V Measured Elevation The self test and self calibration dialog serves as a test of the program has been correctly configured and calibrated A short sequence of regular of regular waves is generated 4 waves to ramp up 6 at full amplitude and 4 waves to ramp down The four waves in the middle is used to compare servo feedback if connected and setup in preferences and wave gauge signals with target values The system performance are checked according to clock phase signal noise signal offset calibration coefficients and phase errors The errors reported on wave gauges is the maximum of all the individual gauges Above given example is a self test performed in an laboratory with AwaSys 6 Here all self tests are passed except for the noise on the wave gauge signal which is higher than normal no analog filter applied to wave gauge signals
49. ow that s is maximum at the peak frequency minimum spread The frequency dependency in AwaSys is taken in accordance with Goda and Suzuki 1975 s f E fort lt f mx fit for f f where Smax is the s parameter for the peak frequency For deep water Goda recommend smax 10 for wind waves Smax 25 for swells with short decay distance and Smax 75 for swells with long decay distance In case of parallel depth contours Smax increases in finite depth due to refraction cf below figure from Goda and Suzuki 1975 S Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 14 AwaSys Help Document Spreading Parameter smex 0 1 0 2 Relative Water Depth A Lo Normal circular distribution D f 6 c exp A cos f Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Main window 15 3 4 Replay stored signal File Edit Run Setup Help Fis Bio g lm Spectral generated signal F2 Replay stored signal F3 A HS Batch run eg r Manual signal F5 Desktop a CAUsersitla Desktop Generation information Libraries Name 4 Jonswap B ta F testaws 25 0 20m Significant wave height Computer 2 0s Peak wave period 4 amp Local Disk C 3 3 Peak enhancement constant J Autodesk 4 Generation parameter
50. rameters Max depth of facility wall height m 2 5 Actual water depth in facility m Sampling parameters Sample frequency Hz Timer type Paddle response fine tuning Constant delay s Mechanical transfer file 1 8 50 Int multimedia Measure gain and delays Absorption Method Absorption parameters Cut off wave frequency low Hz Cut off wave frequency high Hz Absorption filter length Amplification coefficient 0 1 2 gaugesintartield a 1 Preview absorption filter View filter coefficients Absorption filter preview Phase shift filter 1 Phase angle deg KA XK N RR w 3 now ne na n S EZ o ya a Amplification i GN _ T N gt DD _ SG RL ee i ER gt R Phase angle deg 0 2 04 06 08 1 12 14 16 Frequency Hz Theoretical Piston Actual Piston Theoretical Flap Actual Flap 5 28 amp amp Paddle reflection coefficient Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014
51. re identical to the primary channels Digital Output On this page it can be configured to send out digital output to start up servo and to trigger data acquisition software to start for example WaveLab Just a digital output line on a board used by AwasSys need to be connected to a digital input line to the equipment to be controlled At the moment this feature has in AwaSys only been implemented for DAQ boards from National instruments and Data Translation On Data Translation the bit used is always bit number zero on the specified port You can select to use either input board manufacturer or output board manufacturer for the digital output For servo controller start up the digital signal is on when ever the servo needs to gain up to prepare for Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 46 AwaSys Help Document movement The gain up delay of the servo controller can be given The signal is off when servo no longer needs to be gained up no movements For DAQ synchronization with WaveLab the line needs also to be configured in WaveLab This synchronization is very useful when it is needed to know in the acquisition when the generation has started and especially also very useful when running tests in in batch mode The signal i send when the generation starts and removed one second into the test Operation Wave Generator Channels Digital Output Lo
52. ribution 3D 3 D waves irregular gt Direction 0 Cosine distribution Spreading 5 Normal circular distribution Y Corner Reflection Signal File Filename test Path us CAUsers tla Desktop Replay File aws E Wave Gauge File awg E Mod Demand File awd Parameters can be entered for generating waves as regular waves or according to various spectra At Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Main window 9 this time the following spectra are supported RW Regular waves linear 2nd order approximative stream function theory SW Solitary wave piston generator only at start of test piston will move to initial back position half of needed stroke and wait for calm water before generation BM Bretschneider Mitsuyasi MBM Bretschneider Mitsuyasi modified PM Pierson Moskowitz JS Jonswap TMA Texel Marsen Arsloe FRF TMA with Kitaigorodskii s f scaling Custom Spectrum Custom Time Series Custom made spectra read from file Custom made surface elevation time series read from file The list may be extended in future versions The mathematical expressions used for the various spectra are given in the standard spectra section In the table below all input fields at current time are present However depending on the selected spectrum only some of the
53. rue Paddle output buffer length 6000 Elevation input buffer length 512 Oversampling factor 3 Long wave computation kh limit 0 025 Long wave filter length 64 Biesel filter length 4096 White noise filter length 4096 Inverse FFT length 16384 A 49 Warning Alter at your own risk Changes may result in unexpected behaviour This page contains broad variety of program settings which can customize behaviour of the program but most likely never need to be changed The settings can only be changed after checking the change addition settings check box Additional settings Field Gauge calibration freq Hz Description Frequency at which the wave gauges are read during calibration in the calibration dialog see section 6 Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 50 AwaSys Help Document Gauge calibration samples Gauge calibration distance m Gauge zero volt elevation above floor m Preview absorp max freq Hz Preview spectra points Preview spectra max freq Hz Show paddle movement Show elevation history Show paddle history Show on line analysis Show generation info Paddle output buffer length Elevation input buffer length Over sampling factor Long wave filter length Biesel filter length White noise filter length Inverse FFT length Number of samples to average on when calibrating wave gauge
54. s u Civil 3D Project Te White noise A Civil 3D Projects No longwave computation PerfLogs Absorption I Program Files 1 1 Model length scale m Program Files x86 0 5m Water depth a Users 00 20 00 Generation time Ji Public 23 59 59 Calm down time a tla Path C Users tla Desktap E Contacts File testaws Desktop Downloads I Favorites IR Links E My Docume T My Music Preview signal My Pictures My Videos Fileformat Awasys 6 0 gt 3 channels per generator 1B Saved Gam TP Searches 3 m From To dJ WinTeX testaws Replay 0 1200 second Windows e interval A aE sil Files of type 60000 sample Han Zur Signal V on Batch 1 000s 1100s 1 2008 On this page a previous stored wave signal can be replayed By dragging the sliders on the graph in the button of the screen or entering start and stop time in seconds it is possible to replay only part of the signal The wave signal file contains a header with the parameters used at generation time These parameter are shown generation information panel and before replay of a signal AwaSys check that all parameters are correct setup After the header the signal is stored as tne sample number followed by three columns per paddle First column for each paddle is the paddle demand signal including mechanical transfer correction but excluding clipping active absorption gain up and down movement given in voltage The two other c
55. s in the calibration dialog Distance between the wave gauges upper and lower position in meter This is used in the calibration dialog The distance above the floor for the WG zero voltage In case WGs do not have a fixed zero voltage level give a negative value The maximum wave frequency shown on the absorption preview graphs Number of point calculated and drawn on the spectrum preview graphs The maximum wave frequency shown on the spectrum preview graphs Show the real time paddle movement during wave generation Disabling this can ease the stress on a slow computer a little Show the elevation history during wave generation Disabling this will ease the stress on a slow computer Show the paddle movement history during wave generation Disabling this will ease the stress on a slow computer Show the on line analysis during wave generation Show generation info during wave generation Size of buffer to store pre calculated output signals The number of elevation measurements on which the on line spectrum analysis is based A large buffer length gives a good spectral resolution but poor reliability of the energy distribution within the spectrum large scatter This makes the choice of buffer length a weight between fine spectral resolution and scatter If Automatic is entered a proper value for the sea state to be generated will be used Describes the number of times the synthesized signals are over sampled If the over sampling fac
56. se piston order T Various Ke Value Sensitive operation False Warning time s 1 Min input voltage v 10 Max input voltage v 10 Min output voltage v 10 Max output voltage v 10 Paddle offset voltage v 0 Paddle initial voltage v 0 Default gain code input 1 Default gain code output 1 Differential Input True Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 40 AwaSys Help Document This page contains settings related to the hardware involved in generating the waves and the necessary communication setup Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Preferences 41 Main generator settings Field Generator type Elevation position Tapering time s Gain down speed m s Max paddle velocity m s Max paddle acceleration m s Spectrum low cut off freq factor Spectrum high cut off freq factor Spectrum low cut off freq Hz Spectrum high cut off freq Hz 3 D mode generator settings Flap width m Max neighbour pos difference m Description Type of wave generator used Piston Hinged Elevated Piston Elevated Hinge Combined rot below bed level Combined piston and elevated flap For the combined piston and elevated flap two independent actuation modes are used the special issues related to setting up such
57. t Result Servo 2D Feedback channel Gauge filter Eta2 channel O Set const servo delay C Set gauge filter delay Sample frequency Hz Mean 0 114s Mean Amplitude E Volt Std deviation 0 006 Std deviation Delay total 0 000s Wave frequency range Hz Interval step size Hz C Set mechanical transfer file Freq Gain Phase 0 400 1 009 0 287 Set gain of first frequency to unity Fi 0 500 1 016 0 356 0 600 1 026 0 424 Start Stop measuring 0 700 1 036 0 489 0 800 1 049 0 558 0 900 1 067 0 629 1 000 1 079 0 685 1 100 1 101 0 754 Number of iterations Gain and Phase Graph Log 14 z Eo S 0 1 0 0 05 1 15 Time s Fregency Hz MV SendSignal V MeasuredSignal IV Gain IV Phase Absorption performance can be improved by compensation of a possible delay This dialog can measure the delay and performance of the wave generator and hereby automate the process of creating a mechanical transfer file The dialog can also measure a delay introduced by sending the wave gauge signal through a filter Servo delay and gain The dialog measures the gain and phase delay by sending a sinus signal to paddle at varying frequencies and comparing the send signal with the actual movement The actual movement is obtained by connecting the feedback signal from the servo as specified in preferences position feedback channel If feedback signal gain is not proper calibrated there is an option to set
58. t below settings in BIOS and Windows Note that some of the cost of some of these settings to increase timing accuracy is that the PC will use more power BIOS CPU configuration Ensure that the BIOS is up to date from the motherboard manufacturer Disable Hyperthreading Disable C States C3 and above Disable Intel SpeedStep EIST Windows Configuration Ensure that all system drivers are up to date from the chipset motherboard expansion card manufacturer e Apply all updates from Windows Update Third party management software should not be installed or stopped from running at start up except where mandatory To allow AwaSys to set real time class for best timing accuracy the security policy has to be changed Administrative tools gt Local Security Policy gt User Rights Assignment gt Increase Scheduling Priorities An alternative to modify the user rights is simply to run AwaSys as administrator Use regedit to change the value of HKLM System CurrentControlSet Control PriorityControl Win32PrioritySeparation to 28 hexadecimal 40 decimal for short fixed thread quantum without foreground boosting Control Panel gt Power Settings gt High Performance e Control Panel gt Power Settings gt Plan Settings gt Advanced Power Settings gt Switch off PCle Bus Link State Management Control Panel gt Power Settings gt Plan Settings gt Advanced Power Settings gt Disable USB selective suspend setting
59. th the button Admin password In case a password is given the facility settings are not editable unless the administrator login with the button Admin login After admin login the facility settings are editable and also the password can be changed Note setting an empty password removes the password protection The various settings are split into the following tabs Operation Wave generator Primary Channels Secondary Channels Digital Output Look amp feel Additional settings Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Preferences 33 5 1 Operation Below pictures show the operation tab for the two different absorption systems available The figures Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 AwaSys Help Document on the right hand side presents the performance of the absorption system as further discussed below 1 gauge near field li Digital Output Absorption filter preview Look amp Feel Additional Settings Rs232 Phase shift Operation Primary Channels a Model setup parameters Max depth of facility wall height m 4 5 Actual water depth in facility m 1 2 Sampling parameters Phase angle deg Sample frequency Hz Timer type Int multimedia Paddle response fine tuning Constant delay s Mechanical transfer file Measure gain
60. this value Description The number of paddles connected to the system Will automatic setup the stated number of channels using default values from the Wave generator page Data acquisition board number Channel number on the board Transfer coefficient for the paddle in meters per volt Use manual signal to determine this value For the Hinged paddle type this value should give the displacement 1 m above hinge For the Combined mode this should give the displacement at the bed level To lock paddles at mean position specify a transfer constant of zero Gain code for the data acquisition output channel Please refer to the manual of the data acquisition for this value As an extra safety measure a position feedback can be defined for 2 D setups It is an input channel which is either connected to the output channel or the feedback signal from the servo controller If defined AwaSys will measure the value on start up connection and gently gain from current to initially position if there is a difference This will be a very seldom event which only happens if paddle has moved for example during filling of the flume or if AwaSys is aborted closed without moving to initial position Nevertheless this can prevent unwanted shock waves and possible damaging for the model caused by paddle not being in initial position up connection Moreover if the servo feedback is connected to this channel AwaSys can automatically find the mechanical transfer of th
61. tor is 10 this means that the actual sample frequency at which the signal is calculated is 10 times lower than the output sample frequency as specified in operation tab The on line analysis is also over sampled i e an over sampling value of 10 means only every tenths elevation measurement are stored for online analysis Over sampling can be disabled by specifying a value of one Over sampling is always disabled on regular wave generation Length of longwave filter used for long wave computation should be half of Biesel filter length in current implementation method Length of Biesel filter There is an automatic option that sets a proper value for the sea state to be generated Length of filter when using white noise generation method Length of inverse FFT transformation used for random phase generation method FFT length should be long enough to prevent repetition of the signal warning will be given if repetition will occur There exist an automatic option that sets a proper value for the sea state to be generated All the above filter lengths should be as large as possible 2 N in order to give the best statistically distribution of the waves However big filter lengths results in longer computation time Since the input on this page is only partly validated wrong input may cause unintended behaviour Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Preferences 5
62. ulic amp Coastal Engineering Laboratory All rights reserved 2014 All rights reserved No parts of this work may be reproduced in any form or by any means graphic electronic or mechanical including photocopying recording taping or information storage and retrieval systems without the written permission of the publisher Products that are referred to in this document may be either trademarks and or registered trademarks of the respective owners The publisher and the author make no claim to these trademarks While every precaution has been taken in the preparation of this document the publisher and the author assume no responsibility for errors or omissions or for damages resulting from the use of information contained in this document or from the use of programs and source code that may accompany it In no event shall the publisher and the author be liable for any loss of profit or any other commercial damage caused or alleged to have been caused directly or indirectly by this document Printed december 2014 in Aalborg Contents Table of Contents 1 Installing AwaSys 2 Optimal PC configuration for AwaSys 3 Main window 3 1 3 2 3 3 3 4 3 5 3 6 3 7 3 8 3 9 3 10 Spectral generated signal Standard Spectra Spreading functions Replay stored signal Batch run Manual signal Calibrate wave gauges Measure paddle gain and delay Self Test Choose Manufacture 4 Wave Generation 5 Preferences
63. which voltage level the paddle s are in center position Which voltage level to position the paddle s on connection disconnection On connection the paddles will be gained from initial voltage to offset voltage and the opposite on disconnect The input gain code which should be used on Acquisition This value acts like a default value when pressing the auto populate channel button on the channels page since the gain code is stated in each input channel The output gain code which should be used on Acquisition This value acts like a default value when pressing the auto populate channel button on the channels page since the gain code is stated in each input channel Copyright Aalborg University Hydraulic amp Coastal Engineering Laboratory All rights reserved 2014 Preferences 43 Differential input 5 3 Primary Channels 3 D operation 64 generators and 64 wave gauges Wave Generator Look amp Feel Primary Channels Digital Output Additional Settings Are the input channels connected as single ended or differential 2 D operation 1 generator and 6 wave elev explanation below Wave Generator Look amp Feel Secondary Channels Operation Primary Channels LE Wave gauges Wave gauges Number of gauges 64 Number of qauges 6 Auto populate channels Auto populate channels No Brd Ch x Offset Calib Gain No Brd Ch x Offset 0 0

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