OpenLB – Open Source Lattice Boltzmann Code › Forums › on OpenLB › General Topics › Periodic Outlet Boundary Conditions ( nonequilibrium extrapolation method) › Reply To: Periodic Outlet Boundary Conditions ( nonequilibrium extrapolation method) March 29, 2023 at 8:33 pm #7334 FBukreevKeymaster Which particles do you use? Lagrangian or Eulerian? If you have set the periodicity on the particle Lattice there must be no outlet and inlet at all.