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 › Advection Diffusion moddelling › Reply To: Advection Diffusion moddelling November 6, 2024 at 10:54 am #9486 mathiasKeymaster It might be that you need a second internal velocity also be initialized..