A shifting discontinuous-grid-block lattice Boltzmann method for moving boundary simulations

A translating discontinuous-grid-block model for moving boundaries of finite thickness based on multi relaxation time version of LBM has been developed. In this regard, the execution of this model to simulate moving boundary flows has been demonstrated for the cases of a cylinder in simple shear flow, a single rigid wing executing ‘clap and fling’ motion, and the propulsion of a plunging flat plate. It is shown that the implementation of a body fitted refined mesh that moves along with the object improves its resolution and reduces the spurious oscillations registered in the force and velocity measurements compared to a single grid block. A number of interpolation schemes of linear, quadratic and cubic natures are assessed around the discontinuous grid interface. This method is highly suitable for problems that (a) involve large domain sizes in which the moving solid keeps traversing indefinitely in one direction, and (b) a high resolution around the body is demanded without the expenditure of additional computational power and memory as with the stationary discontinuous-grid-block.