[Phicau]

Hi Lin,

current and waves are generated in an uncoupled (independent) way. Since the interaction between wave and currents is complex and nonlinear, it's likely that the BC would need some tweaking or specific formulation to provide more accurate results.

As a temporary solution I would recommend trying generating the currents as in some experimental facilities: setting a small portion of the floor near one end to have an in-flow BC and another part to be the out-flow area near the other end.

Best,

Pablo

[AliVali]

hi all,

could any one help me understanding the "bLims" parameter used in the sample falpWaveGen.py file which is used in olaFlow to generate waves via a flap type wavemaker?

many thanks in advance

[AliVali]

Originally Posted by AliVali

hi all,

could any one help me understanding the "bLims" parameter used in the sample falpWaveGen.py file which is used in olaFlow to generate waves via a flap type wavemaker?

many thanks in advance

it was not a difficult question to be posted here. Indeed, it defines the width of each panel in the wavemaker.

[Aref.shri]

Dear Pablo,
Hi
I am wondering if it is possible to change the waveTheory in the wavemakerFlume tutorial (since it doesn't have any waveDicts)? If yes, how?

[jovenitta]

Hi,

I am not a coastal engineer but quite interested in Breakwater tutorial. The model is the same as given in Higuera et. al (2014) and Guanche et al. (2008). In this tutorial case the given porosity values are not set as in these papers. So this breakwater tutorial case cannot be considered as a validation case on its own, am I right?

As far as I know, a and b values given in PorosityDict are set as by try and see method so we need to set the proper porosity values by comparing the results with an experimental data. I was wondering if there is a physical base for the porosity values given in Breakwater tutorial since they are all set different than the ones in the relevant papers.

Thank you in advance.

[ngj]

Hi,

The values follow from the recommendation in Jensen et al (2014), which is the basis of the implementation in waves2Foam.

As you will find in that reference, multiple combinations of alpha and beta gives a small error, hence it is hard to suggest general values from numerical experimentation.

Kind regards

Niels

[Phicau]

Hi jovenitta,

check my thesis out (page 259):

https://sites.google.com/view/olaflo...del/references

Those are a set of the best-fit values from experimental results.

Best,

Pablo

[Lewis Liang]

Dear Pablo,

I study the tutorial case of random wave in the olaflow, then I set up a 2D case only including 3 single wave components (same wave period, wave period, wave phase, and wave direction). Without doubt, the wave profile is a superposition.

Then I try to separate those wave with different wave phases, but I have not been able to achieve this so for. Here is a silly question of mine due to my limited knowledge, I wonder the olaflow can generate series of single wave, and propagates one by one rather than being a integrated wave resulting from wave linear superposition if I plan to simulate hundreds of wave components?

Many thanks in advance!

Cheers!

Lewis

[Phicau]

Hi Zuodong,

Yes, as stated in the manual, linear superposition is used to simulate irregular waves. You can specify any number of different components and they will be generated independently. I presume that you have an error in your waveDict. Can you upload it so that I can take a look?

Best,

Pablo

[Lewis Liang]

Originally Posted by Phicau

Hi Zuodong,

Yes, as stated in the manual, linear superposition is used to simulate irregular waves. You can specify any number of different components and they will be generated independently. I presume that you have an error in your waveDict. Can you upload it so that I can take a look?

Best,

Pablo

Hi, @Pablo, thanks for your quick reply!

Now, my waveDict is attached below, it includes 101 wave components and generated from the B-M spectrum.

/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  1.3                                   |
|   \\  /    A nd           | Web:      http://www.openfoam.org               |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "constant";
    object      waveDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

waveType        irregular;

genAbs          1;

absDir          0.0;

nPaddles        1;

tSmooth         1;

wavePeriods
101(
1000.00000000000
200.400801603206
111.358574610245
77.1010023130301
58.9622641509434
47.7326968973747
40.0962309542903
34.5661942620118
30.3766707168894
27.0929287455974
24.4498777506112
22.2766763198931
20.4582651391162
18.9143181388311
17.5870559268379
16.4338537387017
15.4225786551511
14.5285485979951
13.7324910738808
13.0191381330556
12.3762376237624
11.7938436136337
11.2637981527371
10.7793467715856
10.3348491112030
9.92555831265509
9.54745083062822
9.19709371838499
8.87154009936125
8.56824608002742
8.28500414250207
8.01988932552731
7.77121541809139
7.53749905781262
7.31743011854237
7.10984713828653
6.91371681415929
6.72811680010765
6.55222120298781
6.38528829576655
6.22665006226650
6.07570326265265
5.93190176770673
5.79474995653938
5.66379700951518
5.53863195790640
5.41887937574510
5.30419561873442
5.19426553085394
5.08879955218564
4.98753117206983
4.89021468042447
4.79662317728319
4.70654680660799
4.61979118543842
4.53617600362894
4.45553377294600
4.37770870726262
4.30255571809655
4.22993951186498
4.15973377703827
4.09182045091861
4.02608905708994
3.96243610571780
3.90076454985177
3.84098329172268
3.78300673375199
3.72675436961950
3.67215041128085
3.61912344830082
3.56760613628255
3.51753491153400
3.46884972942972
3.42149382420365
3.37541348815230
3.33055786844296
3.28687877991060
3.24433053239464
3.20286977131510
3.16245533031846
3.12304809494066
3.08461087633795
3.04710829422878
3.01050666827227
2.97477391718229
2.93987946494194
2.90579415354216
2.87249016172120
2.83994092922867
2.80812108618124
2.77700638711469
2.74657364937241
2.71680069550098
2.68766629935227
2.65915013561666
2.63123273253519
2.60389542755963
2.57712032574801
2.55089026070098
2.52518875785965
2.50000000000000);
waveHeights
101(
0
0
0
0
0
0
1.37972248529053e-79
1.46469593520820e-41
1.13557902623205e-23
2.12511083896587e-14
3.14367436266623e-09
3.52965926996490e-06
0.000268471561817300
0.00426791199812591
0.0262145395570040
0.0884379327275092
0.202118589026308
0.356218524666572
0.525773329942840
0.685927915197279
0.820037393338961
0.920818188640956
0.987984681125312
1.02525382529637
1.03800043294934
1.03180114593863
1.01168864027410
0.981862862524877
0.945655658317546
0.905615578643101
0.863636117035623
0.821087814327909
0.778936534449445
0.737841985932257
0.698236330859707
0.660385175827582
0.624433987276199
0.590442918313625
0.558412653762832
0.528303412461296
0.500048799060821
0.473565813259693
0.448762011771043
0.425540572382821
0.403803820063480
0.383455631264000
0.364403024427433
0.346557163931177
0.329833944610610
0.314154279479014
0.299444180321927
0.285634696525875
0.272661759572017
0.260465967423639
0.248992333330033
0.238190016445120
0.228012046441962
0.218415050494868
0.209358988230124
0.200806898241786
0.192724658328759
0.185080760584412
0.177846101749879
0.170993788745351
0.164498958959601
0.158338614662156
0.152491470771739
0.146937815144714
0.141659380520129
0.136639227260544
0.131861636050433
0.127312009749570
0.122976783642389
0.118843343372198
0.114899949898768
0.111135670867435
0.107540317826223
0.104104388773850
0.100819015565286
0.0976759157426056
0.0946673483970219
0.0917860737032408
0.0890253157997151
0.0863787287180891
0.0838403650922791
0.0814046474023904
0.0790663415311877
0.0768205324313053
0.0746626017199474
0.0725882070346717
0.0705932629991050
0.0686739236612602
0.0668265662796398
0.0650477763436366
0.0633343337250020
0.0616831998664351
0.0600915059217553
0.0585565417697348
0.0570757458305642
0.0556466956201781
0.0542670989833309);
wavePhases
101(
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633
1.57079633);
waveDirs
101{0};

// ************************************************************************* //

At this stage, all thew wave phases of 101 wave components is set-up as the same value. Through the Paraview, the simulated result shows the random wave is superimposed as a wave group and breaking. So, I wonder that, how to modify the wave phase of wave components (the distribution of wave phase), and be able to make each individual wave propagate one by one? i.e. the n+1 wave component generate and propagate after the n wave component.

Cheers!

Zuodong

[Phicau]

Hi Zuodong,

I think you are confused and maybe not understanding spectra and what you are doing.

Spectra represent a sea state and in order to create the free surface elevation time series you need to set the phases randomly. Alternatively, you can also calculate the phases according to linear theory, to obtain a wave focussing.

I don't know what your goal is, but you are setting all the phases to the same value, why?
Also, you can eliminate the first 6 components, they have amplitude 0 and will not have any influence in the final results, but they add computational cost.

Also, I don't understand what you mention about "to make each individual wave propagate one by one". Waves with this method are being generated independently and summed linearly, as you can see in the manual.

Best,

Pablo

[Lewis Liang]

Originally Posted by Phicau

Hi Zuodong,

I think you are confused and maybe not understanding spectra and what you are doing.

Spectra represent a sea state and in order to create the free surface elevation time series you need to set the phases randomly. Alternatively, you can also calculate the phases according to linear theory, to obtain a wave focussing.

I don't know what your goal is, but you are setting all the phases to the same value, why?
Also, you can eliminate the first 6 components, they have amplitude 0 and will not have any influence in the final results, but they add computational cost.

Also, I don't understand what you mention about "to make each individual wave propagate one by one". Waves with this method are being generated independently and summed linearly, as you can see in the manual.

Best,

Pablo

Hi, Pablo!

Thanks for your explanation, and I feel more clearer now. Thanks so much!

Now, my model is modified to propose the random wave including 101 components ( the significant wave height = 3 m, wave period = 10 s, and water depth = 10 m) based on the B-M Spectra. Refer to the wave phases, I use the Matlab code to generate a series of wave phase randomly between [-2pi, 2pi]. Since the the amplitude of first 6 wave components equal to 0, then eliminating them, so totally there are 95 wave components. The modified waveDict is shown below:

/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  1.3                                   |
|   \\  /    A nd           | Web:      http://www.openfoam.org               |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "constant";
    object      waveDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

waveType        irregular;

genAbs          1;

absDir          0.0;

nPaddles        1;

tSmooth         1;

wavePeriods
95(
40.0962309542903
34.5661942620118
30.3766707168894
27.0929287455974
24.4498777506112
22.2766763198931
20.4582651391162
18.9143181388311
17.5870559268379
16.4338537387017
15.4225786551511
14.5285485979951
13.7324910738808
13.0191381330556
12.3762376237624
11.7938436136337
11.2637981527371
10.7793467715856
10.3348491112030
9.92555831265509
9.54745083062822
9.19709371838499
8.87154009936125
8.56824608002742
8.28500414250207
8.01988932552731
7.77121541809139
7.53749905781262
7.31743011854237
7.10984713828653
6.91371681415929
6.72811680010765
6.55222120298781
6.38528829576655
6.22665006226650
6.07570326265265
5.93190176770673
5.79474995653938
5.66379700951518
5.53863195790640
5.41887937574510
5.30419561873442
5.19426553085394
5.08879955218564
4.98753117206983
4.89021468042447
4.79662317728319
4.70654680660799
4.61979118543842
4.53617600362894
4.45553377294600
4.37770870726262
4.30255571809655
4.22993951186498
4.15973377703827
4.09182045091861
4.02608905708994
3.96243610571780
3.90076454985177
3.84098329172268
3.78300673375199
3.72675436961950
3.67215041128085
3.61912344830082
3.56760613628255
3.51753491153400
3.46884972942972
3.42149382420365
3.37541348815230
3.33055786844296
3.28687877991060
3.24433053239464
3.20286977131510
3.16245533031846
3.12304809494066
3.08461087633795
3.04710829422878
3.01050666827227
2.97477391718229
2.93987946494194
2.90579415354216
2.87249016172120
2.83994092922867
2.80812108618124
2.77700638711469
2.74657364937241
2.71680069550098
2.68766629935227
2.65915013561666
2.63123273253519
2.60389542755963
2.57712032574801
2.55089026070098
2.52518875785965
2.50000000000000);
waveHeights
95(
6.89861242645266e-80
7.32347967604100e-42
5.67789513116023e-24
1.06255541948294e-14
1.57183718133311e-09
1.76482963498245e-06
0.000134235780908650
0.00213395599906295
0.0131072697785020
0.0442189663637546
0.101059294513154
0.178109262333286
0.262886664971420
0.342963957598639
0.410018696669481
0.460409094320478
0.493992340562656
0.512626912648187
0.519000216474672
0.515900572969316
0.505844320137048
0.490931431262439
0.472827829158773
0.452807789321550
0.431818058517811
0.410543907163955
0.389468267224723
0.368920992966129
0.349118165429853
0.330192587913791
0.312216993638100
0.295221459156812
0.279206326881416
0.264151706230648
0.250024399530410
0.236782906629847
0.224381005885521
0.212770286191411
0.201901910031740
0.191727815632000
0.182201512213717
0.173278581965589
0.164916972305305
0.157077139739507
0.149722090160963
0.142817348262937
0.136330879786008
0.130232983711819
0.124496166665017
0.119095008222560
0.114006023220981
0.109207525247434
0.104679494115062
0.100403449120893
0.0963623291643796
0.0925403802922058
0.0889230508749395
0.0854968943726753
0.0822494794798006
0.0791693073310781
0.0762457353858697
0.0734689075723572
0.0708296902600645
0.0683196136302721
0.0659308180252164
0.0636560048747848
0.0614883918211943
0.0594216716860989
0.0574499749493841
0.0555678354337174
0.0537701589131117
0.0520521943869252
0.0504095077826431
0.0488379578713028
0.0473336741985109
0.0458930368516204
0.0445126578998576
0.0431893643590445
0.0419201825461396
0.0407023237011952
0.0395331707655939
0.0384102662156526
0.0373313008599737
0.0362941035173359
0.0352966314995525
0.0343369618306301
0.0334132831398199
0.0325238881718183
0.0316671668625010
0.0308415999332175
0.0300457529608777
0.0292782708848674
0.0285378729152821
0.0278233478100890
0.0271335494916654);
wavePhases
95(
3.13839840845723
-1.33298187956605
-0.537070727721836
-0.220917162180514
1.65849123730671
1.99933494194988
-2.51188214477057
-2.02245082596888
-0.881939849250384
-2.78530658438772
0.137511743186277
-1.03139131046841
-2.03783158740519
-1.82874198157208
2.54565488908837
1.10201526844804
-0.198120143072128
2.58950470675397
-2.48806865515939
1.54281148251827
1.48451220556950
0.388686798410772
-1.98426700641103
0.610796928133897
-1.25703296437796
-2.29887341268478
-1.80577782290566
2.48149173232261
-2.69264139012958
-1.61800466929006
-2.80384384626763
-0.366171114785462
-3.05813184358163
2.49562686057596
-1.90595279505218
-2.55492839459043
-1.21034946618563
-0.276097822050594
-2.50278501337687
3.11262545813017
-1.05499184182141
-1.27330750886617
-2.75175103061357
-1.26767051146971
-2.85035906701236
0.0341060249355167
1.64258729016772
0.823537093270891
-2.57678675419534
-2.63351906467447
1.74195366579891
2.54553667233350
0.212195431137193
-2.45575651226785
2.04711742862726
-1.01726203442105
-1.29450548610706
1.54763290990880
-3.07664576508864
-2.83718904342200
1.05504810790997
0.650108515768986
0.164006629567828
1.44330702999651
1.30221205379562
1.76794415764273
-1.33217995160482
1.20971414802588
0.356067074406176
-0.650179035649927
-2.75460707929693
1.76039478289657
-1.02049067903707
0.677741483660137
1.51584389912991
-2.48303163162404
-2.33804626477828
0.311269672513996
-0.0928063629573366
2.45343105026263
1.87842283126740
1.47240845394706
-2.81906490097873
-2.68364081318172
-2.58535821967966
1.87459376578512
2.78350223351160
1.15431898525628
-2.31169096692148
1.39941955511973
-2.44822128542166
-2.40336329125077
0.884156786036332
-1.07559201063806
0.966429440441339);
waveDirs
95{0};

// ************************************************************************* //

Also, I uploaded the case folder here. It will be very grateful if you can help me have a look. Please point out my mistakes.

Cheers!

Zuodong

[kclement1993]

Hi all,

I am running a simple case about solitary wave run-up,which wave comes left to right through a horizon bed to a slope at the right. When the wave run-up at the slope ,and reflecting run down back ,I want the reflecting wave absorpting by the inlet face ,which is like the inlet face is an open patch. However, the default about the inlet is setted to be a wall type and the wave will be reflect again. So I wonder how to do it as I said: set inlet as a outlet patch like.


Hope someone can advise me , I am truely a newhand who just learn everything from 0.

James.

[kclement1993]

I already find the answer :P
Just set the genAbs value of waveDict to be 1~

[A H Gazi]

Hello everyone. i am trying to modify the breakwater case in olaFlow.I am abegginer in this field.I am confused about the setFieldDict.....in blockmesh and in setfield the coordinate range is not matched?....any kind of help is appreciated.How to define that range in boxtocell and surfacetocell?Thanks and regards

[jovenitta]

Hi. I wasn't able to open your files but as far as I know they do not need to match. In blockmesh you define the limits of your solution domain. In setfields you primarily define your water depth.

Originally Posted by A H Gazi

Hello everyone. i am trying to modify the breakwater case in olaFlow.I am abegginer in this field.I am confused about the setFieldDict.....in blockmesh and in setfield the coordinate range is not matched?....any kind of help is appreciated.How to define that range in boxtocell and surfacetocell?Thanks and regards

[Phicau]

Hi kclement1993,

yes, you are right, active wave absorption for wave generation boundaries can be activated setting genAbs equals to 1.

Hi A H Gazi,

the coordinates do not need to match. When you define a boxToCell you are setting the value of the cells whose centre is inside the box that you define.

This box can be anywhere, but you need to be sure that there are some cells inside it. If you define a box that is outside the domain, OpenFOAM will not complain or warn you, but no cell values will be set.

Best,

Pablo

[lincui]

Originally Posted by Phicau

Hi jovenitta,

check my thesis out (page 259):

https://sites.google.com/view/olaflo...del/references

Those are a set of the best-fit values from experimental results.

Best,

Pablo

Hi Phicau,

Is this set of \alpha and \beta values only valid for the condition described in your thesis? It seems that these coefficients depend on both the porous media properties and flow regime. How do I determine these coefficients if the conditions (geometry of the breakwaters, porosity, wave characteristics, ) changes? I am confused about the determination of these coefficients. Do I use the same values in the TUTORIAL for other conditions? Thanks in advance!

Bests,

Lin

[Phicau]

Hi Lin,

you are right, friction factors are material and flow-regime dependent.

Do you have experimental data?
-YES. In that case run an array of cases for different parameters and pick up the set that yields the best results.
-NO. Try the ones in the breakwater tutorial. You better perform a sensitivity analysis of the parameters to see check the degree of change of the solution with respect to the friction parameters.

Best,

Pablo

[lincui]

Hi Phicau,

Thanks for the quick reply.

I don't have experimental data, I am only doing a numerical simulation with several breakwaters. I have used the \alpha and \beta values in the breakwater tutorial and got the results. you mentioned that it is better to perform a sensitivity analysis. but, if the solution differed significantly, how to determine which results are right which are wrong. Also, do you have a recommendation on the range of these value if doing sensitivity analysis?

Bests,

Lin