I am currently working on an analysis in which fluid flows through a pipe causing a turbine to spin. The turbine is fixed in one position on shaft but is able to spin freely. I have been able to get the turbine to move due to the flow, however the resulting angular velocity according to CFD is very high and extremely inaccurate. My thought is that this is due to a lack of assigned friction, however I have no idea how to assign friction to the moving piece. If someone could help me figure out how to assign friction, or if anyone has any other ideas why CFD says the turbine is moving so fast, that would be great.
I suppose you are using rotating region to perform the analysis, how about using the scenario type Known Driving Torque. Use the table input to key in your resistive torque with varying RPM. Don't forget to input inertia as well. Look for here more info.