Search found 47 matches

by Martin FERRAND
Tue Apr 09, 2024 12:32 am
Forum: code_saturne usage
Topic: Drag force calculation
Replies: 6
Views: 85

Re: Drag force calculation

Than you for the precisions. Do you plot the norm of the shear stress or the x component (x being in the fluid direction)? Pressure being defined up to a constant for an incompressible flow, we can shift it from a constant (but the integral of a constant over a closed solid is 0). Another question: ...
by Martin FERRAND
Mon Apr 08, 2024 2:24 pm
Forum: code_saturne usage
Topic: Drag force calculation
Replies: 6
Views: 85

Re: Drag force calculation

hello,

Which version do you use ?

Best Regards,
Martin
by Martin FERRAND
Mon Apr 08, 2024 12:07 pm
Forum: code_saturne usage
Topic: Possible problem in Treatment of Source Terms in Turbulence Models Implementation
Replies: 2
Views: 47

Re: Possible problem in Treatment of Source Terms in Turbulence Models Implementation

Hello, variables are solved in increments, so if a source term write S^{exp} + S^{imp} var then it gives with \delta var = var^{n+1} - var^n : \rho Vol \delta var / \Delta t - S^{imp} \delta var + ... = S^{exp} + S^{imp} var^n Note implicite par is put on the left hand side if - S^{imp} > 0 . Martin
by Martin FERRAND
Thu Dec 08, 2022 10:31 pm
Forum: code_saturne usage
Topic: z_ground divergence atmo module
Replies: 7
Views: 20346

Re: z_ground divergence atmo module

Thank you for your answer. I have no time to check the resu tonight but I can try to answer some of your questions : - z ground is used to imposed initial and boundary profile for the velocity and the (potential) temperature with relief. In Monin Obukhov profiles we take the distance to the ground i...
by Martin FERRAND
Wed Dec 07, 2022 7:42 pm
Forum: code_saturne usage
Topic: z_ground divergence atmo module
Replies: 7
Views: 20346

Re: z_ground divergence atmo module

Dear SimBu,
I suspect there is something wrong in you user subroutines because a ground has already been computed (from 0 to 50m) and should not be computed again.

Do you have any user subroutines which would explain the problem?
Best regards
Martin
by Martin FERRAND
Thu Sep 23, 2021 8:05 pm
Forum: code_saturne usage
Topic: Friction heating in heat transfer
Replies: 9
Views: 3360

Re: Friction heating in heat transfer

Hello, Just to answer to your first question: in the incompressible module the friction source term is neglected and not in the code. You can add it as a user source terme. For the compressible module, the solved equation is the total energy and the terme is handelled. Concerning the wall function, ...
by Martin FERRAND
Wed May 19, 2021 9:02 pm
Forum: code_saturne usage
Topic: [Dispersion in frozen flow] - issue with user scalar value at boundary
Replies: 5
Views: 2388

Re: [Dispersion in frozen flow] - issue with user scalar value at boundary

Hello,

I think you should impose a flux rather a Dirichlet BC because otherwise the ongoing value of scalar is only from diffusion flux.

Could test that?
There is also a possibility to perform scalar balance in the GUI.

Best Regards
Martin
by Martin FERRAND
Mon Jan 11, 2021 9:19 am
Forum: Discussion
Topic: Documentation of rough wall boundary conditions
Replies: 5
Views: 17508

Re: Documentation of rough wall boundary conditions

Hello, Indeed eq I.5.25 has a typo (no Clog). I will correct that. Concerning the two velocity scale, yes there are other references you can read (Craft, and also PHD of Jean-Francois Wald). The derivation of the BCs of k and epsilon is detailed in appendix (which help reading the code). Indeed the ...
by Martin FERRAND
Thu Jan 07, 2021 7:39 pm
Forum: code_saturne usage
Topic: [Saturne 6.0.6] Particles are accelerated by head loss
Replies: 12
Views: 5577

Re: [Saturne 6.0.6] Particles are accelerated by head loss

Dear user, Thank you for the feedback. We are aware of this problem which is due to the fact, if I understand well, that the additional force you have on the mean fluid (with the head loss) is missing in the lagrangian module (all terms on the momentum are not automatically taken as they should). We...
by Martin FERRAND
Wed Jul 22, 2020 5:24 pm
Forum: code_saturne usage
Topic: ALE - mesh viscosity in v6.0
Replies: 12
Views: 8116

Re: ALE - mesh viscosity in v6.0

Dear Daniele, The CDO solver used for ALE is not compatible yet with FSI (and INTERNAL coupling) because the way boundary conditions are treated are really different (using the GUI it is transparent, but you cannot use cs_user_boundary_conditions_ale.f90 for the CDO solver). We check if it is possib...