cfdengineer |
May 20, 2011 14:08 |
Swirl BC problem
I am trying to set a inlet BC by creating two expressions, one for axial velocity and the other for tangential velocity. The radial velocity is zero. The inlet flow has a swirl of 1. The domain it injects into is set as stationary, but the walls adjacent to the inlet is rotating. The axial expression is set as Vax=(mass flow)(swirl)/(density)(Area) and Vtan=(swirl)(pi)(wheelspeed)/30sec. The issue is that when I start CFX it crashes right away with respect to the lower limit exceeded for static enthalpy and a fatal bounds error detected on variable density. Then it shows an Error #001100279 occured in the subroutine ENFORCE_BOUNDS. I was able to create a ramp function and bumped the timestep down and it ran, but I began to get the same static enthalpy limits and a warning with high Mach number. I believe the way I have the BC setup is incorrect. Does anyone out there have any suggestions? The result file I got back had very high circumferential velocities and negative axial velocities. CFX usually creates walls at inlets if there is reversed flow, but it it not do so.
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