transition problem

dirk

Hello, i am simulating the flow in a wind channel over a flat plate. A contoured wall opposite the plate generates a pressure distribution with a strong adverse pressure gradient which induces laminar separation. I am using rke model with enhanced wall treatment and in order to get the separation I divided the channel into two volumes and set the upstream part as laminar zone.

The problem is that there is a small vortex/separation across the plate in the turbulent region right behind the transition point, which is absolutely not physical, even if the laminar flow is not separated. When I put the transition point upstream where there is almost zero pressure gradient this vortex doesn't occur, a fully turbulent flow is also computed fine.

The yplus values are around 1, I tried other turbulence models but the result didn't get better.

If anyone has an idea that can help me, i will be very thankful.