Comparison of Lattice Boltzmann and Finite Volume method for flow past sphere

Three dimensional computations have been carried out using Lattice Boltzmann Method (LBM) and Finite Volume Method (FVM) for the case of flow past a stationary sphere. The Reynolds number of the mean flow have been varied from 50 to 300 during which flow transitions from steady state to unsteady state. The LBM simulations were carried out using the open source solver Palabos developed in the University of Geneva while the FVM computations were performed using the commercial solver ANSYS Fluent 17.2. Qualitative results like streamlines and three dimensional vortex structures in the wake of the sphere, obtained from the two different techniques have been compared alongside results reported in literature. Quantitative results such as, variation of velocity in the sphere wake and length of wake bubble have also been compared. The present study also tabulates the computational time required to complete the flow simulation for the both the solvers while utilizing the same computational resource. The results from the present study highlights the advantages of LBM solver for simulation of unsteady three dimensional flow but also indicate that FVM technique has definitive benefits when it comes to steady flows.