PROTEUS: A coupled iterative force-correction immersed-boundary multi-domain cascaded lattice Boltzmann solver

Most realistic fluid flow problems are characterized by high Reynolds numbers and complex boundaries. Over the last ten years, immersed boundary methods that are able to cope with realistic geometries have been applied to Lattice-Boltzmann (LB) methods. These methods, however, have normally been applied to low Reynolds number problems. Here we present a novel coupling between an iterative force-correction immersed boundary (Zhang et al., 2016) and a multi-domain cascaded LB method. The iterative force-correction immersed boundary method has been selected due to the improved accuracy of the computation, while the cascaded LB formulation is used due to its superior stability at high Reynolds numbers. The coupling is shown to improve both the stability and numerical accuracy of the solution. The resulting solver has been applied to viscous flow (up to a Reynolds number of 100000) passed a NACA-0012 airfoil at a 10 degree angle of attack. Good agreement with results obtained using a body-fitted Navier-Stokes solver has been obtained. The formulation provides a straight forward and efficient method for modeling realistic geometries and could easily be extended to problems with moving boundaries.