[sasanghomi]

Dear friends,

These days, I am using MRF method so as to simulate the fluid flow around a rotor of an electrical generator. In fact, the flow is rotating around the rotor surface (because of the rotational velocity of Rotor (3000 RPM)) and also, there are some fluid flows whose directions are perpendicular to the rotor axis.

The problem is that when I measure torques (In CFDPost software) on the interface of rotating domain, there are different torques on the two coincident interfaces. (The interfaces belong to stationary and rotating domains respectively)

Do you think that it is showing that the simulation has not been done correctly?
I personally suppose that we must have the same torques on the coincident interfaces.

I would be grateful if you could clarify this issue.

Best Regards
Sasan Ghomi

[ghorrocks]

Calculating the torque on a fluid to fluid interface is not meaningful. There is nothing in an interface for the force to act on. Forces act on walls, and in some cases inlet/outlets.