Numerical simulation of external flow around cylinder using improved lattice Boltzmann method

In this study, incompressible and viscous external flow around a cylinder is simulated using the lattice Boltzmann method. The surface of cylinder is considered to be a rigid immersed body in the fluid flow. The fluid flow field is discretised by a uniform and fixed Cartesian mesh but there are difficulties in the modelling of curved boundaries. As a result, the cylinder surface is extrapolated by macroscopic properties at boundary nodes. On the other hand, to well treat with boundary condition of the cylinder surface and in the meantime, to save the computational effort, an innovation is applied in this research which solves this problem by introducing a new curved boundary condition to improve computational accuracy in lattice Boltzmann simulations. However, this method can be extended to other physical fields as well as fluid flow. The present results have been compared with the available numerical results which show good agreements.