|December 9, 2009, 04:57||
Strange behaviour on outlet boundary using LES
Join Date: Mar 2009
Posts: 39Rep Power: 9
I get a nasty inflow on the outlet boundary when doing LES using buoyantBoussinesqPisoFoam in OF 1.6.x (changed to allow generic turbulence models the same way as pisoFoam). The inflow seems to be caused by a very low pressure in the cells closest to the outlet boundary in the south-east corner of the domain.
I'm running a test case for a heavy plume from a chimney surrounded by a number of buildings. I have tried three different meshes with different resolution at the outlet. I tried one mesh with very low resolution of perfect hex cells just before the outlet in order to get a diffuse very "nice" outflow.
I have tried different numerical shemes (linear, upwind, limitedLinear). However, the soultion does not blow up. I've kept the courant number below one (approx. 0.5). I am currently trying to use Smagorinsky but have also tried with oneEqEddy.
The bc:s are:
east (outlet) : U inletOutlet, p fixedValue, nuSgs zeroGradient
west(inlet) : U fixedValue, p zeroGradient, nuSgs zeroGradient
chimney: wall function
building: wall functions
The case is initialized using a converged run with simpleFoam. So far the temperature field is uniform, which should make the solver very similar to pisoFoam.
I have run out of ideas! Has anyone seen a similar behaviour? I have very limited experience of LES, so please tell me if you see something that seems strange in my setup.
|les, outlet boundary, pressure bc|
|Thread||Thread Starter||Forum||Replies||Last Post|
|outlet boundary condition for compressor modeling||siamak1424||FLUENT||3||August 8, 2009 05:55|
|VOF Outlet boundary condition in cfd - ace||JM||Main CFD Forum||0||December 15, 2006 09:07|
|Solver error message!!!||IoSa||CFX||1||September 14, 2006 04:48|
|Outlet boundary condition||CN||FLUENT||6||May 22, 2005 09:37|
|Inlet and Outlet Boundary conditions for LES||Jan Ramboer||Main CFD Forum||12||August 6, 1999 22:00|