Circulation
 

I am simulating a 3D piston/cylinder vortex ring generator in ANSYS CFX. I wonder how can I calculate the circulation in CFX? I want to calculate the vortex ring circulation and the total circulation discharged fron the piston.
The renolds number is higher than 2000

Regards;
Hamed

Can you describe what you are trying to model? A drawing would help.

In this article (ref. pic:0) they have done it experimentally. I want to do it in ANSYS CFX. pic 1 is the schematic of the apparatus. the vortix ring is in pic 2. in pic three the vector velocity field and vorticity contour is there. and pic 4 shows the circulation.
I want to know how can i calculate circulation in cfx.

Regards

So you have done the simulation and you want to post-process the results to get a representative circulation? The paper you refer to should define how they measure circulation. You will have to use their definition for comparable results.

They define it in this way:
"For each case, the maximum circulation of the vortex formed (of either positive or negative sense) was
measured by integrating the vorticity within an iso-vorticity contour (of a given sense)

of 1 s−1."

But I dont know how to do it in ANSYS CFX?

This is all stuff you can do in CFD-Post.

Make a user surface defined by a contour of vorticity=1 [1/s]. Then do a surface integral of vorticity on that user surface using the function calculator. Easy.

thank you very much for yur help.
So if I get you correctly:
I define a plane and plot vorticity on that plane (with the vorticity magnitude of 1 s-1)
then I should define the integral of vorticity on that contour.

can you please tell me how do I define the surface integral for vorticity in the calculator of cfd-post?

Once again thanks for your help

The CFX tutorials show how to do this sort of post processing.

Do you know any tutorial on this i could look?
I would appreciate it if you can refernce any to me

regards