I am trying to simulate a simple laminar flow through a pipe. I have drawn the pipe with cylindrical simple drawing method and set the boundary conditions but it still gives me an error: Error 74 "There are cracks (unconnected regions) in the model" What can I do to get rid of this error?

It is not really important. You can make a VMER, or use the function CHECK to check the double cells, but if the problem still exists, you can run the calculs, it will work.

thanks, it worked