OpenLB – Open Source Lattice Boltzmann Code › Forums › on Lattice Boltzmann Methods › General Topics › addSlipBoundary › Re: addSlipBoundary March 28, 2018 at 7:45 am #2820 mathiasKeymaster Dear Mario, it looks like your geometry is somehow irgegular. The slip BC works for boundaries which are parallel to lattice directions. Best Mathias