# Initialize Pressure Field in Lattice Boltzmann Method with pressure-based equilibrium

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 November 13, 2017, 08:12 Initialize Pressure Field in Lattice Boltzmann Method with pressure-based equilibrium #1 New Member   Julia P. Join Date: Nov 2017 Posts: 1 Rep Power: 0 I am currently learning about Lattice Boltzmann Method for incompressible Navier-Stokes Equation. Specifically speaking about free surface waves from the following paper : click here It used ILBGK pressure-based equilibrium distribution function by Guo. Basically I understand the overall algorithm of method used in that paper, but I'm confuse how to initialize the distribution function using this model, especially the pressure field which is usually unknown. I want to simulate the propagation of solitary wave over a flat bottom. From the references I've read so far, initial and boundary condition usually state in velocity while the pressure is unknown. I also read consistent initialization by Mei, but it seems it will lots of iteration. Other reference also say that the initial pressure can be found by solving the pressure-poisson equation by Gauss-Seidel Method. I've tried use the latter, but by using different initial pressure at iterative method, I get different result or is it okay to initialize the pressure by constant value? or am I missing some important concept about LBM? Thanks in advanced : Last edited by julia.p; November 13, 2017 at 19:51.

 November 13, 2017, 19:49 #2 Senior Member   Arjun Join Date: Mar 2009 Location: Nurenberg, Germany Posts: 1,150 Rep Power: 30 if i remember correctly the pressure is result of density and density is equation to sum of probability F functions. In case of incompressible formulations i am not sure how it would work.