OpenFOAM | First Tutorial – pitzDaily

PitzDaily is the case most people run first in OpenFOAM. It is a backward facing step: the flow enters a narrow channel, the wall drops away, and the stream separates and reattaches further downstream.

It works as a first case because the geometry is trivial and the physics is not. Separation and reattachment are exactly what turbulence models struggle with, so the case has been measured experimentally and used for validation for decades.

Running it also teaches the structure of any OpenFOAM case: the initial time folder holding the boundary conditions, constant holding the mesh and the physical properties, and system holding the numerical settings. Generate the mesh with blockMesh, run the solver, and open the result in ParaView. Every later case follows the same three folders.