[Jung hoo]

Hello pablo! I'm using IHFOAM well for my academic purpose and I'm really appreciative of your effort.

I'm simulating regular waves passing though simple vertical breakwater by using IHFOAM.

I want to get the overtopping flow rate by time above the breakwater and I think that it is possible through paraview using 'plot over line', 'integrating values' and 'plot selection over time' but I'm not sure it is working...

I read your paper 'Three-dimensional interaction of waves and porous coastal structures using OpenFOAM.Part 2 : Application' and I will be very thankful to you if you give me the way you plot 'Fig. 14. Space-time series of instantaneous overtopping discharge rate'.

Thank you so much in advance.. your any comment will very helpful to me..!!

[Phicau]

HI Jung Hoo,

that graph was not performed in paraview. I used OpenFOAM sampling tools to get the flow rate over the crown wall and then postprocessed them with matlab to obtain the final plot.

Best,

Pablo

[Jung hoo]

Thank you for your reply Pablo!

I have used 'sampleDict' recently, and now I can calculate some values like pressure and water surface level by time using 'sampleDict' and 'postSensPres.py', 'postSensVOF.py'.

but I can't understand that overtopping flow rate can be calculated by using 'sampleDict'... it must be due to my poor knowledge.. ....

Do you use 'alpha.water' as filedname in 'sampleDict' ??

If so, calculating overtopping flow discharge above a breakwater through 'sampleDict' seems to be so complicated to me..

If it doesn't hurt your feelings, could you show me the contents of 'sampleDict' that can be used for calculating overtopping flow discharge??

If the answer of my question is so complicated in writing, please just post any references about it!

And I'm very appreciative of your previous kind reply about 'p_rgh'!.. it helped me to understand 'pseudo-dynamic pressure'.

Thank you in advance and I'm always thankful for your effort you made until now in openfoam!!

[Phicau]

Probably you will be better off cutting with a plane in paraview and exporting alpha and velocity. There is plenty of information on how to do that in the forum. Then you can obtain overtopping with your favourite programming tool.

Best,

Pablo

[Jung hoo]

I'll try it using paraview! Thanks a lot!!

[rcarmi]

Hi,

I am not sure how to select the proper value for the k-Eps model. I see in the tutorial of breakwater the values of k and eps are set to 0.0001 but in other tutorial to 0.1
Here is what I have set so far (I have only solid boundaries which should be equivalent to plexiglass)
epsilon
internal field uniform 0.0001
bottom => type epsilonWallFunction with value 0.0001
inlet outlet => type zeroGradient
atmosphere => type inletOutlet with value 0.0001
k
internalField uniform 0.0001
bottom => type kqRWallFunction with value 0.0001
atmostphere and inlet outlet idem previous

and the kEps coeffs are left unchanged
Cmu = 0.09
C1 = 1.44
C2 = 1.92
sigmaEps =1.3

Is there a rule for the waves?

I am interested in waves for water depth of 0.15m period 0.65s and wave height 0.035m.

Thanks for any advice!

Carmi

[GrivalszkiP]

Hi!

I'm trying to simulate our wave flume with flap wavemaker. In my simulations, waves smearing quite quick. How can I decrease this numerical diffusion error?

Main parameters:

- flap wavemaker:
motionType flap;
x0 (0 0 0);
n (1 0 0);
waveHeight 0.05;
initialDepth 0.15;
wavePeriod 0.55;
rampTime 2.0;
wavePhase 0;

- k-Omega SST turbulence model
- 5 mm gridsize around water surface (flume is 0,5 m wide)
- MULES, (isoAdvector makes weird errors...) with
nAlphaCorr 2;
nAlphaSubCycles 3;
cAlpha 2;

Thank you:

Peter

[IHFOAM Team]

Hi Peter

Originally Posted by GrivalszkiP

How can I decrease this numerical diffusion error?

A first idea would be to deal with the over-prediction of the turbulence kinetic energy. Please, take a look to the "New multiphase turbulence stabilization" (link), based on the works B.Devolder and B.E.Larsen & D.R.Fuhrman.

Best Regards,
IHFOAM Team