OpenLB – Open Source Lattice Boltzmann Code › Forums › on Lattice Boltzmann Methods › General Topics › the geometry definition in cavity 2d problem › Reply To: the geometry definition in cavity 2d problem February 15, 2021 at 1:27 pm #5475 mathiasKeymaster This is just for the renaming of material numbers. No, dont relpace it because it should not be too big. By it you make sure that only the lid material numbers are renamed.