Counter Rotating Case Boundary Conditions . . . The Fundamental Error?
 

Hey everyone.

I'm trying to simulate a problem of "counter-rotation". I want to use MRF approach. My domain comprises of a stationary domain and two "counter-rotating" domains with no gap in between them.

The interfaces between the two rotating domains and the stationary domain have been defined using Frozen Rotor. Other BCs are as follows:

Inlet: Velocity
Outlet: Pressure
Surrounding Walls: Wall BC

Mesh has been created in ICEM CFD with Quality of around 0.3 and Min Angle of around 18.

I have tried running this problem in CFX, Fluent and STAR CCM. The error I get after only a few iterations is 'overflow' in CFX and 'reverse flow on outlet' in STAR.

I have tried extending the outlet further downstream. I have applied an "Opening" BC in CFX. But the error is persistent.

Can someone kindly point out what is it that I am missing here? Thanks.

Could you attach another figure explaining better what exactly is your region of interest and a schematic of the problem to be solved? Right now it is hard to understand who is rotating, where are the inlets and openings, etc.

Thanks for your reply.

The image below is a better respresentation of the BCs I'm using for the simulation.

I have a mass flow/velocity inlet. A pressure outlet. The remaining walls of the stationary domain are 'walls'. There are two rotating domains inside the stationary domain.

As it turns out, there is nothing wrong with the BC's at all. I had not 'scaled down' the mesh. The domain length was '15 km'. I have scaled it down now and it's up and running.

Thanks.