New to LBM and OpenLB? Attend our upcoming one-week hands-on Spring School in Marseille/France from 19.05.2025 – 23.05.2025. OpenLB – Open Source Lattice Boltzmann Code › Forums › on OpenLB › General Topics › Velocity boundary conditions › Reply To: Velocity boundary conditions May 18, 2021 at 11:37 am #5676 mathiasKeymaster it is basically there ot distigish betwwen bounce back boundaries (0.5) and other (1.0).