CFD Online Discussion Forums

CFD Online Discussion Forums (
-   OpenFOAM Running, Solving & CFD (
-   -   Relative velocity in simpleSRFFoam (

miku November 4, 2008 09:39

Hi, I have a question to simpl
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!

paul_mathis November 4, 2008 10:21

Hi Miku, Urel is the relati
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 November 4, 2008 10:35

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


miku November 4, 2008 11:26

Thanks for your answers! If I
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?


dmoroian November 4, 2008 11:51

Hi Miku, The relative velocit
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).


All times are GMT -4. The time now is 08:21.