Hi

When we have both Mach number and Reynolds number at inlet boundary of a compressible flow on a turbine blade, from which one we should use to get velocity?

If you have Reynolds and Mach number in your problem, and the temperature and characteristic length are also given, then you have redundant information. Check if you don't get the same velocity from both numbers. You could ask this question in the main forum, (it is not really cfx-specific), you may get faster and better answers

You can get the velocity from both! And you should obtain same velocity from both Reynolds number and mach number.

Peace Usman

If the Reynodls and Mach number are both based on the full scale and you are modeling the full scale device, they should be the same. If you are scaling the geometry and attempting to match the non-dimensional quantities, the Mach and Reynolds numbers will return different values. In that case you'll need to determine which non-dimensional parameter dominates the physics.

-CycLone