I finished a 3D case using cartesian coordinate, now i need convert the outlet velocity (Vx,Vy,Vz) to cylindrical velocity-(V(axis),V(tangetial),and V(radical)). How to do that in Fluent postprocessing? Appreciate your response.

Dear Intern,

you can use the Define -> custom field functions option to define the velocity component transformations. You have to be a bit careful though with trig functions and signs but Ihave done it sucessfully before.

Let us know if you have further trouble.

Regards,

Bak_Flow

Bak_flow, thanks for your reply. The custom fuction method may work out but its implementation on arbitrarily located surfaces will be pretty troublesome.

I found a better way on the Fluent online support website, which allow us define a local (cylindrical) coordinate at the postprocessing stage. Thus we can get the cylindrical results directly, without any further conversion.

The way to do this is as following: define -> Fluid B.C's-> Rotation-Axis origin, axis direction, reference zone, etc.

Finding the origin and axis direction are also pretty tricky. You can search the online support to find more details on this.

Again, many thanks.