Dear Friends,

Happy new year!!

In my simulation, I only change "upwind" to "high resolution", the result is different obviously. And the result of upwind is close to experiment result.

The fluid in my model is compressible air and the speed is 311 m/s at inlet.

Could you give me some advice?

Thank you very much.

Best Regards Eric

The upwind discretisation scheme is a first order procedure which trend to a high dispersion variable gradients in the streamingarea. depending on wheter there are high velocities in the mesh area the value of the variables from a previous mesh point can be assigned to the next one in the streaming direction with high accuracy. approximately this is what the upstream scheme does. in most of cases it is a bad decision to choose a first order procedure to solve the simulation. but in your case with high velocities (311 m/s = 1120 km/h) without areas with sharp gradients like velocity fields close to walls it should be a good discretisation scheme.

Happy New Year to you, too!