Ansys Assistant will be unavailable on the Learning Forum starting January 30. An upgraded version is coming soon. We apologize for any inconvenience and appreciate your patience. Stay tuned for updates.
Rob
Forum Moderator

At the speeds you're seeing chances are there is enough compression/expansion of the flow to divert the particles. As each turbulence model will interact differently that could cause the banding. How many stochastic tries did you use? 

[bingo_chatbox]