One can write the data in VTK format out of the OpenLB but I did not find a matlab script that can read VTK format. I need matlab to do some postprocessing of the resulting 3D fields. Does any one know a solution to this issue? Thanks.

One thing you can do is save the data in pure text format instead of VTK. Here’s a routine which flushes the content of a lattice or a data field into a text file:

I don’t know of any interface which reads VTK data into Matlab. But I guess it would be easy to write one, using the VTK library and the Matlab native code support (“mex files” ).