I am unable to view the contours of velocity stored in the pvd file in ParaView. It only shows the option of pressure field. Does this have to do anything to the way the .pvd file is created in openLB? In the contourBy option only the Physpressure field shows up?
The countours are not explicitly stored in the VTK file. Instead it contains the raw vector fields of e.g. the velocity in this case (really any functor) from which you can then compute and visualize contour lines in ParaView.
As the contour tool there expects a scalar field you will first have to apply some norm to the velocity field. Alternatively you can also use the results of e.g. OpenLB’s euklid norm functor.
Thank you so much for your help. I stored the scalar field of velocity separately using calculator tool in ParaView, and now I can plot the contours of velocity field. The problem is resolved.