Search found 8 matches

by Jean-Francois Wald
Tue Apr 09, 2019 12:54 pm
Forum: Code_Saturne usage
Topic: Low value of Turbulent heat fluxes in Natural convection
Replies: 7
Views: 583

Re: Low value of Turbulent heat fluxes in Natural convection

Hello Everyone, I am running Rayleigh Benard natural convection case with Rayleigh number to be 630000 and Pr as 0.71. I am using AFM as turbulent heat flux model. For boussinesq implementation, I am adding boussiesq(rho*beta*(T-t_ref)*g) source term in momentum equation. I am facing an unusual pro...
by Jean-Francois Wald
Tue Nov 27, 2018 2:33 pm
Forum: Code_Saturne usage
Topic: Umist_wall_function
Replies: 8
Views: 2012

Re: Umist_wall_function

Those 2 layers "standard" wall functions are not the one implemented in the code. Again, please have a look at the Theory guide that you can access via the command line I gave you before or here . This will give you an overview of what is implemented in clptur.f90 and cs_wallfunctions.c/.h As explai...
by Jean-Francois Wald
Tue Nov 27, 2018 12:21 pm
Forum: Code_Saturne usage
Topic: Umist_wall_function
Replies: 8
Views: 2012

Re: Umist_wall_function

Hello ! I strongly advise to read the clptur section in the theory guide (code_saturne info -g theory) you will have some better insight in how wall functions are computed. All boundary conditions are imposed through the clptur routine. Whether you have to modify or not the production in the turbke ...
by Jean-Francois Wald
Thu Sep 20, 2018 6:30 pm
Forum: Code_Saturne usage
Topic: Problem using k-omega SST model to simulate flow around a circular cylinder
Replies: 4
Views: 972

Re: Problem using k-omega SST model to simulate flow around a circular cylinder

Hello Lei, Thanks a lot for sharing your test case. You are right concerning the Neumann type BC for Omega in the code. We are currently working on an similar issue. Could you try to set the Neumann constant of Omega BC to 6.75 instead of 120 and see if this improve your results ? Could you also ple...
by Jean-Francois Wald
Tue May 22, 2018 3:15 pm
Forum: Code_Saturne usage
Topic: Temperature field with the RSM-EB model
Replies: 4
Views: 682

Re: Temperature field with the RSM-EB model

Dear Andrea, I think the behavior you get is typical of the use of EBRSM turbulence model combined with SGDH for temperature. The latter is intrinsically wrong when used with low Reynolds RSM models. In this case nu_t is computed through its k-eps expression C_mu k^2/epsilon, but this expression is ...
by Jean-Francois Wald
Thu May 03, 2018 8:15 am
Forum: Discussion
Topic: wall function implementation, k-epsilon
Replies: 6
Views: 1703

Re: wall function implementation, k-epsilon

Fluid properties such as dynamic viscosity are already passed as argument to the wallfunctions subroutine and are thus accessible in the "cs_wall_functions.h". I assume you're trying to implement wall functions similar to the UMIST analytical wall functions from Craft et al. (2002) which requires ad...
by Jean-Francois Wald
Mon Apr 30, 2018 1:42 pm
Forum: Discussion
Topic: wall function implementation, k-epsilon
Replies: 6
Views: 1703

Re: wall function implementation, k-epsilon

Dear Ionut, I'm not familiar with the Windows versions of Code_Saturne. When dealing with code modification going beyond modification of user subroutine, installing the code through sources (under Linux) and then re-compile/re-build the sources with those advanced modifications is usually preferred....
by Jean-Francois Wald
Fri Apr 27, 2018 3:18 pm
Forum: Discussion
Topic: wall function implementation, k-epsilon
Replies: 6
Views: 1703

Re: wall function implementation, k-epsilon

Dear Ionut There are currently no dedicated user files that enables the user to prescribe user defined wall functions. It is however possible to modify a wall function or even to add one through sources. Wall boundary conditions are set in the clptur.f90 file that you 'll find in the src/base direct...