[Phicau]

Hi Zahra,

flapWaveGen.py only changes the paddle movement, you need to change the rest of parameters as you did with the mesh. Water level is set at system/setFieldsDict.

Hi Mohammad,

not at this moment, but it should not be difficult to modify it for that purpose, as it is completely open source. One of the challenges would be for it to calculate the free surface location, as it currently integrates alpha.water over the water column, you would need to add the second fluid on it. A similar thing will occur with velocities.

Best,

Pablo

[stev122]

Good Morning Pablo,

I wish to appreciate your generous support for the olaFoam. I am very new to coastal modelling but I am fortunate to be able to install your olaFoam and I have run most of the tutorials.

I do not seem to seem to see some samples of the time series because I am attempting to set up double peaked waves for overtopping assessment using olaFoam.

I have created the wave time series using Matlab and I want to implement the velocity profile and waves in your olaFoam. Please, your advice will be valuable in order implement this.

Thank you sincerely,
Stephen

[stev122]

Good Morning Pablo,

I wish to appreciate your generous support for the olaFoam. I am very new to coastal modelling but I am fortunate to be able to install your olaFoam and I have run most of the tutorials.

I do not seem to seem to see some samples of the time series because I am attempting to set up double peaked waves for overtopping assessment using olaFoam.

I have created the wave time series using Matlab and I want to implement the velocity profile and waves in your olaFoam. Please, your advice will be valuable in order implement this.

Thank you sincerely,
Stephen

[stev122]

Good Morning Pablo,

I wish to appreciate your generous support for the olaFoam. I am very new to coastal modelling but I am fortunate to be able to install your olaFoam and I have run most of the tutorials.

I do not seem to seem to see some samples of the time series because I am attempting to set up double peaked waves for overtopping assessment using olaFoam.

I have created the wave time series using Matlab and I want to implement the velocity profile and waves in your olaFoam. Please, your advice will be valuable in order implement this.

Thank you sincerely,
Stephen

[Phicau]

Hello Stephen,

thanks.

What do you mean with double peaked waves? Double peak spectrum?

If you have a spectrum you can discretise it into different components and use the irregular wave type (see reference folder for an example). This is the option that would fit most conditions, since the time series of elevation and velocity profile is for a constant velocity profile along the water depth.

Best,

Pablo

[stev122]

Oh Pablo,

Many thanks for your quick feedback. Yes. You know one the spectrum is generated. I can form the wave types easily.

[stev122]

Originally Posted by Phicau

Hello Stephen,

thanks.

What do you mean with double peaked waves? Double peak spectrum?

If you have a spectrum you can discretise it into different components and use the irregular wave type (see reference folder for an example). This is the option that would fit most conditions, since the time series of elevation and velocity profile is for a constant velocity profile along the water depth.

Best,

Pablo

Yes, Pablo. I wish to see the sample of such file and how I can implement it. I do not see any example on it at all.

[stev122]

Dr Pablo,

I have discretised the spectrum into new time series. I think my major problem is how to incorporate it into olaFoam at moment. I need help on the data format and how to load in the time series to be able to generate the waves.

I do not see any tutorial on this mode.

many thanks, you are such a great inspiration to us.
Stephen.

[Phicau]

Hi Stephen,

as I said, you need to discretize the spectrum into different components (wave height, period and phase) and create a waveDict file as in OLAFOAM/reference/waveDict/irregular

Best,

Pablo

[kenneth0811]

Hello everyone.

I am olaFOAM user. I am a master course student in civil engineering. Through olaFOAM I can learn a lot about the CFD analysis.

My research topic is "Numerical Analysis on Wave Characteristics around 3D porous Submerged Breakwater in Wave and Current Coexisting Field."

My question is
1) I used the LES model(kequation) as a turbulence model. but When I read olaFOAM manual and Pable Higuera's paper, OlaFOAM was used k-e model in prous structures. So, is LES model not applicable to prous structures?

2) I modeled the sand beach(D50=1mm and prosity=0.3) behind the submerged breakwater. When i read Pable Higuera's Ph.D. thesis, a and b(resistance coefficient in closure term) was confirmed as best fit value in dam break(case CR and GB) but not a sand. So, is sand beach modeling possible in olaFOAM? and Is there any information or formula about the best fit of a and b besides the dam break?

Sorry, I do not speak English well. I hope everyone understands.

[stev122]

Dear Dr Pablo,
Thank you very much for your brilliant help. It really helped me and I am able to generate my waves based on your instructions. Please I am having issue setting up proper gauges to measure the free surface.

Please do you habe any advise for me on this. I am able to use the sampling graph but that is a long thing. What I want is thw time series immediately and not at every time steps that the graph is producing.

Please kindly help me. The sampleDictVoF in the reference file did not work for me as well.

Thanks
Stephen

Originally Posted by Phicau

Hi Stephen,

as I said, you need to discretize the spectrum into different components (wave height, period and phase) and create a waveDict file as in OLAFOAM/reference/waveDict/irregular

Best,

Pablo

[Phicau]

Hi Ju Hyun Bae,

if you use LES, you will not have the turbulent enhancement due to the closure terms that are modeled for my modified k-epsilon, but since I have not released that part, you are fine. In fact, as referenced in literature, looking for the best-fit a and b parameters already may take into account some contribution from those terms if no closure model is used.

Sand modelling is possible, as long as porosity is not very low. There is no reference for a and b values for sand, you would need to obtain them based on experimentation, as I did for the dam break case. Try to find experiments to obtain them by best-fit analysis.

Hi Stephen,

I think what you are looking for is already included in the breakwater tutorial included in the olaFoam release. Check runCase for all the steps necessary to run and sample the results, and focus on postSensVOF.py

Best,

Pablo

[Aref.shri]

Hi all!
I'm working with an example in OLAFOAM OF300_400 named wavemakerFlume. I've added a body (caisson) to the domain which has no motion yet. Now I want to add a 6-DOF motion to the body that moves with the wave in additional to an oscillating flap (wave maker that existed in the example before) and have two different kinds of movement. Does anybody have any idea how to set dynamicMeshDict file?

[stev122]

Ok Dr Pablo

I will give it a try.

Thanks a lot. You are a life saver here...
Stephen

Originally Posted by Phicau

Hi Ju Hyun Bae,

if you use LES, you will not have the turbulent enhancement due to the closure terms that are modeled for my modified k-epsilon, but since I have not released that part, you are fine. In fact, as referenced in literature, looking for the best-fit a and b parameters already may take into account some contribution from those terms if no closure model is used.

Sand modelling is possible, as long as porosity is not very low. There is no reference for a and b values for sand, you would need to obtain them based on experimentation, as I did for the dam break case. Try to find experiments to obtain them by best-fit analysis.

Hi Stephen,

I think what you are looking for is already included in the breakwater tutorial included in the olaFoam release. Check runCase for all the steps necessary to run and sample the results, and focus on postSensVOF.py

Best,

Pablo

[ramesh.naidu]

Friends any body have an idea about creation of user define function in ansyscfd

Sent from my ASUS_Z00LD using CFD Online Forum mobile app

[kenneth0811]

Thank you for your reply.^^

If I experiment with the best fit of a and b, analyze the value, or have other information, I'll post it here.

[abas.rahmani86]

Hi Pablo
I read several paper and thesis about porous media to know "how i can extract governing equation from RANS" and i really confused about this. for example vanGent extract Forchheimer eq. from NS but in other references Forchheimer eq. is a source term of RANS.
please introduce me reference to know how i can do this exactly.

thanks a lot

[Phicau]

Hi Abas,

in reality no one extracts anything from RANS. Similarly to what happens when you convert NS into RANS, there are some new terms that appear because of the averaging and that you cannot solve (e.g. Reynolds stresses) under the assumptions that you used in the averaging process. You can only model them.

The same happens when you volume-average RANS, there are certain forces that should appear because of the solid skeleton of the porous medium, but they have been filtered out. That is why we include different terms, as Forchheimer, nonlinear drag and added mass to approximate their effects. And that is why they need to be estimated from best-fit.

Best,

Pablo

[abas.rahmani86]

Thanks pablo
I have another question
I read Jensen 2014 and volume averaging procedure but i dont see any extra term equivalent for Cm
But in this paper we add both Fi and Cm
I found Fi and why it is exist but for Cm i dont have reason


Tnx

[Phicau]

Cm is added mass. When you understand the concept of added mass you will see that this term needs to come into play. In these cases it has a very mild contribution, and the flow barely changes if you consider very different values of Cm, that is why no one uses it for the best-fit.

Best,

Pablo