A multi-block lattice Boltzmann method for fluid flows

Compared to Navier-Stokes equation-based approach, the method of lattice Boltzmann Equation (LBE) offers an alternate treatment for fluid dynamics. However the LBE method often employs certain regular lattices to maintain a compact and efficient computational procedure. This limitation makes it difficult to perform flow simulations when there is a need for high resolution near the body and/or there is a far-field boundary. To resolve these difficulties, a multi-block method is developed. In this method, the flow field is divided into blocks. In each block, the grid is uniform and the grid size is chosen according to the desired resolution. In this paper, an accurate interface treatment between neighboring blocks is derived to ensure the continuity of mass, momentum, and stresses across the interface. Several test cases are employed to demonstrate that the present multi-block method can greatly improve the accuracy and computational efficiency.