Implementation of curved wall boundary and absorbing open boundary conditions for the d3q19 lattice boltzmann method for simulation of incompressible uid ows

Abstract

In this study, a three-dimensional lattice Boltzmann method was developed for the numerical simulation of fluid flows around arbitrary geometries in a wide range of Reynolds numbers. For the efficient simulation of high Reynolds number flow structures in a turbulent regime, a Large Eddy Simulation (LES) approach with the Smagorinsky subgrid turbulence model was employed. An absorbing boundary condition based on the concept of sponge layer was improved and implemented to damp the vorticity fluctuations near the open boundaries and regularize the numerical solution by significantly reducing the spurious reflections from the open boundaries. An off-lattice scheme with a polynomial interpolation was used for the implementation of curved boundary conditions for arbitrary geometries. The efficiency and accuracy of the numerical approach presented were examined by computing the low to high Reynolds number flows around the practical geometries, including the flow past a sphere in a range of Reynolds numbers from 10" to 10 and flow around the NACA0012 wing section in two different How conditions. The present results were found in good agreement with the numerical and experimental data reported in the literature. The study demonstrates that the present computational technique is robust and efficient for solving How problems with practical geometries.