OpenLB – Open Source Lattice Boltzmann Code › Forums › on OpenLB › General Topics › Curved boundary › Reply To: Curved boundary November 11, 2024 at 12:17 pm #9512 FBukreevKeymaster Yes, material 0 is the problem here. You just leave the channelas it is in the main method and create a cylinder in the prepareGeometry section like: IndicatorCylinder3D cyl(center1, center2, radius); superGeometry.rename(1,2,cyl);