Due to recent bot attacks we have changed the sign-up process. If you want to participate in our forum please send a message via our contact form. › Forums › OpenLB › General Topics › why is the defineRho in VelocityBM empty? › Re: why is the defineRho in VelocityBM empty? October 13, 2014 at 2:31 am #2146 LeafMember thank you so much