Turbulent shallow water flow
 

Hello everyone,

With an algebraic (Mixing lenght) turbulent shallow water flow, I can not see recirculation developed around an obstacle. My simple question is: can the number of mesh have an effect on the capturing of turbulent behavior? or I have to use other models?

Thanks.

Please post the plot of the solution

with pleasure

Well, the grid resolution appears very coarse but that depends on the Reynolds number of the flow. Are you sure that the run is convergent?

However, if you are using RANS then you would not be so surprised that you do not capture a great recirculating region behind the bluff body.

I'm not sure for the convergence, because I'm not the responsable of the runs. I'll check this point.

Indeed, I use the RANS model. Is this the problem ?

Thank You

What is the goal of the simulation? If you want to observe the vortex shedding, RANS is not the correct formulation.

We want to develop a numerical scheme based finite volume method for the tubulence shallow water flows. We start with the RANS model involving many turbulence models (Minxing lenght) and K-epsilon model. As an example we try to compare all on a wake turbulent.

Hello,

Firstly i think mesh size around obstacle don't have good quality, you can keep actually size of mesh on the geometry but you have to refine it around obstacle.

Attachment 59816

Attachment 59817

I don't recommend triangular meshes because they are very diffusive. Your problem may be meshed without any problems with hex elements.

Hi,

Due to simple probleme and geometry he can do it with 3D so i recommand you to use tetraedral element and insert prism layer on the wall and around obstacle to obtain the effect of viscous forces near the wall.

Thanks all for the replys

Nourlil, I appreciate your remark to refine near obstacl, I well do it and post results.

Piu58, I have all time the problem of numerical dissipation but I never had the idea that the rectangular mesh is little diffusive. Sadly, I work with a personal code, is mush diffuclte for me tu converte to a rectangular mesh only for this problem.

No problem you are welcome, which soft do you use to simulate ? if you want i can help you to simulate your calculation with static and dynamic obstacle.

Best,