OpenLB – Open Source Lattice Boltzmann Code › Forums › on OpenLB › General Topics › Poiseuille 2D Center Velocity Error (Forced,bounceBack) › Reply To: Poiseuille 2D Center Velocity Error (Forced,bounceBack) July 7, 2021 at 6:02 pm #5809 mathiasKeymaster Standard bounce back in general work like this with the wall assumed to be located 1/2 off the nodes. In the mentioned example we have show how to realize it. Best Mathias