See the MRF development
From OpenFOAMWiki
Reynolds-Averaged Navier-Stokes formulation in the rotating frame.
Acceleration term expressed for a rotating frame around the z axis ().
Notation: I: inertial, R: rotating
General vector:
Position vector:
For the accelration, the velocity vector is:
Eqn [1]
Navier-Stokes equations in the inertial frame
Eqn [2]