OpenLB – Open Source Lattice Boltzmann Code › Forums › on OpenLB › General Topics › why is the defineRho in VelocityBM empty? › Re: why is the defineRho in VelocityBM empty? October 11, 2014 at 9:30 am #2145 mathiasKeymaster Hi openlb12,rnrn For velocity boundary cells the density is to be interpolated and therefore rho is not to be set. So the code is correct.rnrnMathias