BFS: steady?
Hello,
I am solving a backward facing step at a Re=37000. Stepratio=8/9 and inletvelocity= 44.2m/s From the literature I understood this is a steadystate problem. Howver I have problems with convergence solving this with RANSBaldwin Lomax model. Now I found an article claiming that it isn't steadystate. What is your opinion on this? Greetings, Jan R. 
Re: BFS: steady?
(1). The backward facing step problem is a steadystate problem. (2). Are you using the steadystate formulation or the transient formulation? (3). If you are having the convergence problem with the steadystate formulation, then try to use a more stable firstorder scheme to get the converged solution first. From there you can then switch to a highorder method. (4). If you are having the convergence problem with the transient formulation, there is no much you can do, except to use a more smooth mesh, a lower order scheme, and a smaller time step. (5). There could be a feed back effect between the flow field and the turbulence model. So, in this area, you can use a relaxation factor to slow down the change between iterations. (6). It is likely that the method you used is not very stable. This would be the case when using the transient formulation.

All times are GMT 4. The time now is 15:42. 