[SarahMP]

Hi all,

I am trying to simulate the oscillatory pitching of a 2D transonic aerofoil.
Im having some issues with convergence.

Im using the transient, density based solver and SST k omega model.
I have prescribed the motion using the CG_MOTION UDF for the entire domain as a rigid body.

When using a pitching amplitude of 1, the calculation is completing as expected, there is some warnings of reversed flow at the outlet (12%) but other than that it is okay.

The problem is when I increase the pitch amplitude to 2.5 which is required for my comparison case, the solution is diverging and failing. There is also much higher reversed flow at the outlet (35%).

I have tried decreasing CFL, reducing time step size, and using first order methods rather than second order.

Im not sure what else I can do to help with convergence, or whether it is an issue with my prescribed boundary conditions or motion.

If anyone has any suggestions it would be greatly appreciated!

Thanks,
Sarah