3-D Compressible Flow Boundary Conditions

Tyler

I am having problems with convergence on a 3-d compressible external flow problem. I am trying to model Mach 0.8 axial flow around a solid cylinder. The flow field is external, so I have tried using "pressure far-field" boundary conditions on the 6 faces of the flow field volume. However, whenever I run the simulation, I can never get convergence with the continuity equation. I also get errors stating the pressure and temperature have been limited to a certain value.

The flow volume is a rectangle with a cylinder in the middle. No elements are even close to being skewed, so I don't think it is a mesh problem. Are there better/more appropriate boundary conditions for external flow? Any help or assistance is greatly appreciated. Please let me know if more details are needed.

-Tyler