# Fluid momentum equation in a rotating reference frame

1. Sep 21, 2012

### AngrySaki

(specifically equations 7.2 and 7.3 in the pdf)

They derive the acceleration in the inertial frame in terms of the velocity seen in the rotating frame (7.2), then apply that equation of acceleration to the conservation of momentum equation and that's the equation of motion in the rotating reference frame.

How come you don't also have to apply the equation $\vec{u}_{I} = \vec{u}_{r} + \Omega \times \vec{r}$ to all the instances of the velocity $\vec{u}$ in the conservation of momentum equation?

Thanks

Last edited by a moderator: May 6, 2017