I am working on modeling a compressible, turbulent, supersonic flow problem that involves the large scale motion of multiple components of a mechanism (motion is large relative to length scale of the moving bodies) where the body motion is driven by the fluid induced forces (pressure and viscous) as well as user defined resistance, spring etc forces.

I need to be able to apply user defined mass and heat sources that are functions of current flow variables and locations in the system.

I also need to apply a real gas model.

I have looked at CFX but have found the mesh motion limited to small scale motion due to the main use of the grid stretching.

I have spent a long time trying to get FLUENT to work. WHile the motion and user functions suit the needs, the run times are unreasonable and parallel scaling with a moving deforming mesh is poor.

Does anyone have any experience in modeling this type of a problem, recommendations for a code, or comparisons to the run time using FLUENT.

I am working on a problem very similar with yours,but i can not work it out now.i think the main problem is the moving situation of the piston can not be defined.