[miku]

Hi, I have a question to simpleSRFFoam. I cannot find a definition of Urel. Relative to what is Urel? And why does simpleSRFFoam use Urel instead of U absolute?
Thanks in advance!

Hi Miku,

Urel is the relative velocity in the rotational frame, the absolute velocity would then be:

Uabs = Urel + omega x R

where omega is the angular velocity vector and R the position vectro in rotational frame.

[dmoroian]

Hi Miku,
Maybe you will find this answer satisfactory: relative velocity formulation


Dragos

[miku]

Thanks for your answers!
If I have not defined a rotational frame and my rotational axis is equivalent to the z-axis of my stationary coordinate system, I am right that my relative velocity is equivalent to my absolute velocity?

miku

[dmoroian]

Hi Miku,
The relative velocity is identical to the absolute one, when there is no transport velocity (in your case 0 rotation or 0 rpm).

Dragos