Axisymmetric Venturi model not converging. Please help.

I am having an issue getting a supersonic converging - diverging nozzle model to get a solution to converge. The model is set up using axisymmetric periodic rotational constraints. The model is outputting a solution ratio that is growing rather than moving to zero like it should and I am unsure how to fix this. My initial boundary conditions may take part but I am unsure. Attached is the model