[fg118]

Hi Niels,

I have try to generate focus wave as post #47 suggested with combineWaves. The focus wave is really generated, but I am confused with the focus time and focus point. With newwave method, when you input focus time and focus point, the focus wave will be generated at focus point on focus time. But with combineWaves, the focus time and focus point seems not on the input value. I have shift each wave phase with omega(i)*t(focus)-k(i)*x(focus). Any suggestion?

Best Regards

Feng

[kev4573]

Hi Niels,

I am trying to use the 5th order Stokes theory to simulate deep water waves. However it seems that the mean water level gets shifted by about the amplitude of the wave. I'd expect some shift of the mean level on the order of the second/third order wave amplitudes, but the results I am seeing seem odd to me.

Case: https://www.dropbox.com/s/q60gv6pcuq9z2k8/wfd_5th_problem.tar.gz

Kind regards,
Kevin

[ngj]

Hi Kevin,

I agree, it does look weird - do not think I ever tried running 5th order - merely implemented it for fun

I am out of the office for a couple of days, but I will try to get a change to look into it. If you stumble over a bug before that time, please report it here.

Kind regards,

Niels

P.S. What is the vertical resolution/sample accuracy relative to the reported error?

[kev4573]

Niels,

The cell size in the vertical is 0.00333m and the shift in mean water level is about equal to the wave amplitude (0.0125m).

Cheers,
Kevin

[rosswin]

Originally Posted by ngj

Hi Ross,

If you have tried the standard tutorial "damBreak", then you will see that you will get a directory for each time data is outputted.

If you do not have those in the output, when running waveFoam, then something is wrong. If you are running in 1.7.1. then all you need to do is to execute "./Allwmake" to compile library, utilities and solvers and nothing else; and it has proven to work.

Which tutorials in waves2Foam have you been running?

/ Niels

Hi Niels,

Sorry for the late reply and thank you for trying to help me out.

I have uninstalled all openFOAM versions and reinstalled OpenFOAM 171. AS of yet I haven't run any waves2Foam tutorials but I have managed to run A few OpenFOAM tutorials and they worked.
At the moment I am reinstalling waves2Foam: I am stuck on Instruction 2 of this installation https://github.com/ogoe/waves2Foam

I have run ./Allwmake and I get this response

make: Target `application' not remade because of errors.

I then changed my directory to /opt/openfoam171 and executed ./Allwmake again
for which I got this response

make: Target `application' not remade because of errors.

after a long list of errors.


Regards
Ross

[ngj]

Hi all,

@Kevin: You are using a solution to the linear dispersion relation, however, you are using a fifth order stokes theory. This does not match, which results in a negative stokes drift in your case, hence a lowering of the water level.

In the attached figure, the black line is with correct k(period,depth,height), whereas the white line is the incorrect linear dispersion relation.

@Ross: You give far too little information to resolve your problem and furthermore, you have achieved the source code from a to me unknown source. Try download the latest release directly from the SVN given on the wiki.

Kind regards,

Niels

[kev4573]

Hi Niels,

Great, thank you for taking the time to look at this. I noticed the negative flow from the domain and now it makes sense.

Kind regards,
Kevin

[ngj]

No problem - I can really recommend using setWaveParameters, because it does resolve this type of problems, and the dispersion relation for the specific wave theory is already implemented.

/ Niels

[kev4573]

That's what I started using for the fifth order waves and it seems to be working well now.

By the way, I did take a good look through the 5th order theory implementation and was unable to find any mistakes .

[ngj]

Kevin,

Did you find the time to test the compilation of waveFoam based on 2.1 on 2.1.1?

/ Niels

[kev4573]

Niels,

Yes the waveFoam solver based on 2.1.0 is cross compatible with 2.1.1 (no changes required).

Kevin

[ngj]

Hi Massoud,

I have been going through the solitary and as I see it, it is implemented as it is given in the reference already discussed.
I have updated the header, and it will come out later today with a large update. Please see the announcement thread.

Kind regards,

Niels

[sunliming]

Hi,ngj:
I'm now working on wind-wave interaction problems for wind engineering application as my master's thesis, and my foremost concern is wind profile over waves rather than wave itself. I've read your paper about the wave generation toolbox, very nice job. But I wonder whether your toolbox can take into account of wind forces on waves(given a natural wind field rather than a uniform zero) and whether the coupling effect of air and water can be considered. I wanna use LES but your toolbox is based on RANS(if I'm right), is that compatible with LES for upper wind field?
Thank you in advance!

[daveatstyacht]

Sunliming,
Currently only uniform wind velocity has been implemented by adding:
wind (0 0 0) into the waveProperties file (default is uniform zero if omitted).

The addition of uniform wind was made primarily with moving objects (ships) in mind as before then only uniform zero was present. You could utilize existing boundary conditions like swak4foam to produce a wind gradient, however you would likely have to develop a modified version of wave2foam to avoid the profile being overwritten in the domain. Regarding LES and RANS, wave2foam is built on the interFoam solver which is generic in the choice of turbulence model (RANS, LES, Laminar).

[sunliming]

Originally Posted by daveatstyacht

Sunliming,
Currently only uniform wind velocity has been implemented by adding:
wind (0 0 0) into the waveProperties file (default is uniform zero if omitted).

The addition of uniform wind was made primarily with moving objects (ships) in mind as before then only uniform zero was present. You could utilize existing boundary conditions like swak4foam to produce a wind gradient, however you would likely have to develop a modified version of wave2foam to avoid the profile being overwritten in the domain. Regarding LES and RANS, wave2foam is built on the interFoam solver which is generic in the choice of turbulence model (RANS, LES, Laminar).

Hi, Dave:
Thank you for your reply! But I'm still a little bit confused of "swak4foam to produce a wind gradient", I want to add uniform pressure gradient as a driving force for wind (like in channelFoam), can swak4Foam fullfil that? In interFoam two-phase flow is solved using a general U-equation, how to add the pressure gradient to air alone excluding the water part since the interface is unknown brefore solving?

[daveatstyacht]

Sunliming,
Swak4foam is a library that combines groovyBC and funkysetfields. It is a very flexible way to define boundary conditions and field values. This would be your best bet for being able to define a pressure gradient for air and not water (you could define a function for it). I can't really offer any specifics on how you actually go about setting up this with swak4foam since I haven't really used it. There is plenty of post about swak4foam and a OF wiki article on it.

[ngj]

Good morning,

Another option is that the boundary condition, wavePressure, in waves2Foam is based on the mixed type boundary condition, so it is relatively easy to give a pressure gradient in the air or an absolute value of the pressure.

How this would interact with the relaxation zones is not very clear on the other hand, but an inlet relaxation zone might not be of your interest?

Anyway, good luck

Niels

[sunliming]

Dave and Niels,
Thank you for your advice, I'll try it out.

[janepen]

Hi, Ngj,

I am quite curious which nonlinear dispersion formulae or codes used for fifth stokes wave. Could you please pass me some references or codes?


Regards,

John

Originally Posted by ngj

Hi all,

@Kevin: You are using a solution to the linear dispersion relation, however, you are using a fifth order stokes theory. This does not match, which results in a negative stokes drift in your case, hence a lowering of the water level.

In the attached figure, the black line is with correct k(period,depth,height), whereas the white line is the incorrect linear dispersion relation.

@Ross: You give far too little information to resolve your problem and furthermore, you have achieved the source code from a to me unknown source. Try download the latest release directly from the SVN given on the wiki.

Kind regards,

Niels

[ngj]

Hi John

Yes, I have found out that I lack some information in the header files. Here is the reference:

@article{ ISI:A1985AEB7500005,
Author = {FENTON, JD},
Title = {{A 5TH-ORDER STOKES THEORY FOR STEADY WAVES}},
Journal = {{JOURNAL OF WATERWAY PORT COASTAL AND OCEAN ENGINEERING-ASCE}},
Year = {{1985}},
Volume = {{111}},
Number = {{2}},
Pages = {{216-234}},
Publisher = {{ASCE-AMER SOC CIVIL ENGINEERS}},
Address = {{345 E 47TH ST, NEW YORK, NY 10017-2398}},
Type = {{Article}},
Language = {{English}},
Affiliation = {{FENTON, JD (Reprint Author), UNIV NEW S WALES,SCH MATH,KENSINGTON,NSW 2033,AUSTRALIA..}},
ISSN = {{0733-950X}},
Research-Areas = {{Engineering; Water Resources}},
Web-of-Science-Categories  = {{Engineering, Civil; Engineering, Ocean; Water Resources}},
Number-of-Cited-References = {{13}},
Times-Cited = {{134}},
Journal-ISO = {{J. Waterw. Port Coast. Ocean Eng.-ASCE}},
Doc-Delivery-Number = {{AEB75}},
Unique-ID = {{ISI:A1985AEB7500005}},
}

The code is all implemented in waves2Foam.

Kind regards,

Niels