OpenLB – Open Source Lattice Boltzmann Code › Forums › on OpenLB › General Topics › Changing Pressure Outlet by time › Re: Changing Pressure Outlet by time December 27, 2017 at 9:01 am #2765 mathiasKeymaster Dear Arash81068, the two line asign the kind of bc. The value is set be “sLattice.defineRho”. You can define that within the time loop for changing boundary pressure values as it is done for the velocity in that very example. Best Mathias