CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   CFX (http://www.cfd-online.com/Forums/cfx/)
-   -   Momentum Source Convergence (http://www.cfd-online.com/Forums/cfx/22715-momentum-source-convergence.html)

Doug June 15, 2006 17:04

Momentum Source Convergence
 
Hi. I'm trying to simulate air flow through a fan by adding a general momentum source to a subdomain, however I am having convergence problems.

Convergence of v-momentum eventualy causes divergence of u-,w- momentum equations (at about max-v-mom= 1e-02).

(using upwind, timestep auto. but reducing t results in same)

Seems the worst residuals are right at the boundaries of the subdomain where the source is added (1e-02). But Grid refinement seems not to help. Overall velcity field looks realistic (vmax approx 5m/s).

Anyone have any experience / problems / ideas with adding momentum sources?

------

axial component: -500 * parabolic_distribution r component: 0 theta comp: 0

Momentum source component: -1e+05

NOT redistributed in Rhie Chow <-- seems to do nothing

NOT incl. Coeff. in Rhie Chow <-- seems to do nothing

Rotation Axis: GlobalY

------


Joe June 16, 2006 05:54

Re: Momentum Source Convergence
 
You should not be using the upwing scheme. Are you sure your source size calculations are accurate? Manual contains a good section on dealing with convergence issues "Advice on flow moddeling".


All times are GMT -4. The time now is 00:24.