|August 16, 2009, 04:39||
Best outlet BC for instationary results
Join Date: Mar 2009
Location: Davis, CA, United States
Posts: 60Rep Power: 8
I am using OpenFoam for a while now and I am getting some fair results with it, but I have to admit, that my boundary conditions are mostly taken from suggestions from this message board.
I am trying to resolve unsteady vortex shedding behind a bluff body on a shorter grid and therefore I am looking for a "better" outlet condition than a pressure out - which I used until now.
Perfect would be a BC which would allow in- and outlet but I am not quite sure how to apply such an BC.
inletOutlet or outletInlet seem to be a start but how do they differ ? and what else is there to specify in the BC patch ?
Thanks for your advise.
|August 16, 2009, 05:26||
Join Date: Mar 2009
Location: Braunschweig, Niedersachsen, Germany
Posts: 275Rep Power: 9
having an outlet with flow coming back is a very bad idea and should be avoided by extending the domain and keeping the cell count in bay using aggressive cell size increase towards the outlet.
However, there are cases where this is difficult or where you simply want to stabilise a steady-state run to get over the first few iterations.
@1: inletOutlet is zeroGradient where the flow goes out and fixedValue where the flow comes in --> This should be used on an outlet boundary. OutletInlet is just the opposite.
@2: My suggestion for an outlet patch without corners:
totalPressure on p
inletOutlet on U, k, epsilon
This can be improved, but see how is works for you first.
|Thread||Thread Starter||Forum||Replies||Last Post|
|pressure outlet BC for Boussinesq with Fluent||stephane||Main CFD Forum||1||October 20, 2007 07:09|
|Inlet & Outlet Boundary Conditions||dhananjay||Main CFD Forum||2||December 21, 2006 11:03|
|Inlet & Outlet Boundary Conditions||dhananjay||Main CFD Forum||0||December 18, 2006 03:51|
|VOF Outlet boundary condition in cfd - ace||JM||Main CFD Forum||0||December 15, 2006 09:07|
|pressure outlet BC for incompressible flow||khaiching||Main CFD Forum||6||October 15, 2005 02:58|