On an explicit method for pre-estimate flux for incompressible flow simulation

For incompressible Computational Fluid Dynamics (CFD) problems, the finite volume method (FVM) often uses explicit velocity flux to linearise the convection term. This makes the convergence sensitive to the initial velocity field. The pre-estimation of the initial field is a common strategy to stabilise and/or speed up the solving process. A common technique is to pre-solve a potential flow problem. Here we present an alternative method to pre-estimate the initial flow field for incompressible flow problems. The method will be based on explicit cell-wise flux balancing combined with face shear corrections. This distinguishes it from a typical potential flow pre-estimation where no viscous effects are considered. We will also demonstrate the effectiveness of the method in terms of increasing the convergence speed of CFD simulations on the popular open source platform OpenFOAM in both 2d and 3d scenarios.