[cgs2]

i just started working on cfx and i have trouble in obtaining parabolic velocity profile of inlet in setup procedure.

How to obtain such parabolic velocity?
If you could tell me detailed expression of this kind of profile it would be better.

[urosgrivc]

You can use Expressions where you include height into the equation.
something like this...

Velocity=y*c1+c2^2 ... [m s^-1]

if y is your height. but the equation depends on where your coordinate system is positioned and the velocity of the flow (this is just an example and does not represent exactly what you need!).
You can also plot the profile prior to the computation to check if it is ok or not.

Then where your inlet boundary condition is you just right click and call this expression which already has proper units.

is this 2D, 3D? where is the coordinate system?... few data is missing to tell more

[cgs2]

i'm trying to put parabolic velocity profile(maximum velocity 20m/s) inlet to a 3d cylinder(radius 0.2m) which rotate around y-axis, thank you!

[karachun]

Here is a set of expressions.
If you make the cylinder axis coincident with Z axis, then you can use the predefined variable "r" and get rid of the "TubeRadius" expression.

[siw]

This is also covered in CFX Tutorials Example 11: Flow Through a Butterfly Valve.

I guess most people by-pass the tutorials that come with CFX and just go straight into trying to model their own simulations.

[karachun]

Sometimes people bypass whole fluid dynamics institute course.