|May 6, 2009, 02:48||
Weak rotational flow - Convergence Problems
Join Date: Apr 2009
Posts: 6Rep Power: 10
I am simulating seawater flow in a subsea particle filtration unit, with weak to moderate rotating flow induced by stationary curved fins.
I get convergence using all k-epsilon models using SIMPLE pressure.velocity coupling, but when switching to k-omega (standard and SST) the solution only converge for 1st Order Upwind. When switching to higher order schemes the residual oscilliates around a specific point quite far from the convergence criteria of 0.001. It is mainly the continuity residual that struggles.
I have tried under-relaxation and PISO, but they dont do the job.
As inlet condition I have velocity inlet, and the outlet is an outflow. Most of the flow is laminar, but a certain region is turbulent so I figured I had to use turbulent modelling.
Is there any basic steps I can apply in order to figure out the problem, and is it possible that the k-omega turbulence modelling law just doesn't apply in this case?
|May 8, 2009, 09:45||
Join Date: Mar 2009
Posts: 67Rep Power: 10
I have no experience with water, but it could be, that there are problems with your grid - see also: http://www.cfd-online.com/Forums/flu...cillation.html
If just some region is turbulent, you might use a "laminar zone" in this regions to suppresses all turbulence (in the fluid BC).
Another option would be, to change the gradient option (-> define -> models -> solver) . I have no idea, what is really behind this settings, but they helped me sometimes...
Hope, that helps a little.
CFD - nothing but Colourful Fluid Dynamics
|Thread||Thread Starter||Forum||Replies||Last Post|
|Flow meter Design||CD adapco Group Marketing||CD-adapco||3||June 21, 2011 08:33|
|convergence problems using SBF=1||Fonzie||CFX||1||March 23, 2007 09:46|
|Convergence problems with SSG turbulence model||Ram||CFX||1||June 19, 2006 10:08|
|Convergence problems||Emilien||FLUENT||3||May 3, 2002 08:43|
|convergence problems||david aquilina||CD-adapco||4||October 27, 2000 09:18|