Hello,

I'm according to studying cfd to simulate flow through rotating machine using sliding mesh technique. and I need to know how to apply Navier Stoke eq. to rotating part of domain. Is it just the Navier Stoke eq in rotating reference frame or not. Could anybody please tell me.

Thanks for all comment.

Jakie

You have to choose between relative and absolute variables (like relative and absolute velocity), and between rotating and fixed coordinate system. So you have four possible combinations. I think the two most popular ones are

a) Relative variables on the rotating frame. In this case your equations need to be supplemented by centrifugal and coriolis terms. You also need to implement a conversion method, to transfer variables across the sliding interface.

b) Absolute variables on the rotating frame. Again, your momentum equations need to be changed. It's equivalent to introducing coriolis and centrifugal terms, but this time it's more appropriately viewed as a new time derivative of the absolute quantities, caused by rotation. This case may be less intuitive but it simplifies the transfer of variables across the interface.

Review your undergrad dynamics textbook to see how the new terms arise in the equations.