Help! Visualizaion of secondary flow
 

Hi

How can I get a visualization of the secondary flow in a turbine rotor cascade in CFX? Should I use CEL ?

I define the secondary flow velocity vector like this : i-direction is the rotating axis. U_ave is the area-weighted average of velocity vector of the plane perpendicular to i. The local velocity vector of the secondary flow : U_sec = U_local - U_ave .

If someone know how to do this,please help me. Thank you very much!

Re: Help! Visualizaion of secondary flow
 

Hi,

In CFX-5.7.1 Post you may create a variable and define it as a vector (this was not possible to do in CFX-5.6). You have to set expressions for the 3 components of the vector.

If the i-direction is the x-axis, for example, you may create an expression for U_ave as areaAve(u)@Plane. Then create the vector variable U_sec, and define the 3 components as:(u-U_ave,v,w).

If the i-direction doesn't correspond to any of the axis, it will be a bit more complicated but possible.

Regards,

Rui

Re: Help! Visualizaion of secondary flow
 

Thank you Rui , That's very kind of you.

Re: Help! Visualizaion of secondary flow
 

A very simple way to visualize the flow is to create a slice plane through your model perpendicular to the axis of rotation. On this plane, create streamlines using the "Surface Streamlines" option. This will create streamlines on the 2D surface only, thus the secondary flows.

Regards, Robin

Re: Help! Visualizaion of secondary flow
 

Robin

Thank you very much for your smart idea.