Desired region extraction from a flow field/domain.

Ciao tutti,
I uploaded a vtk file (of flow field/domain of the sea bed) and a porous cylinder of stl file. I scaled the cylinder into the center of the flow field. now I am interested to only extract the flow region of the cylinder form the entire flow field to analize whats the flow behavior inside the cylinder such as to see velocity, vorticity etc. Please anyone guide me how to extract this region from the flow field and then how to analize?
Thank You!

This is not a trivial operation, vespa or vtkbool should be able to help.


@idrees if this is just a one time operation, you may try the to Clip filter, setting Clip Type to Cylinder, and playing with the widget.
You can have this kind of result:

Do you need a more accurate / robust solution ?

Thank You for the positive response. As in the screenshot that I shared, the lower part of the circular shape is hidden into the flow field and the shape is not uniform. The diameter keeps decreasing towards the bottom and also not straight but bended one side. Is there any way that could extract the flow field accordingly?