Due to recent bot attacks, newly registered users are required to send a message via our contact form in order to be able to post in the forum. OpenLB – Open Source Lattice Boltzmann Code › Forums › on OpenLB › General Topics › Poiseuille2D: Interpolated and local values(velocity and pressure) › Reply To: Poiseuille2D: Interpolated and local values(velocity and pressure) August 6, 2021 at 8:14 pm #5900 mathiasKeymaster You can use the unitConverter to get rho for pressure and initialize this rho. Best Mathias