Immersed boundary-lattice Boltzmann simulation of a rotating flat plate interacting with laminar flows

Abstract

To make an insight into the interaction characteristics of a flat plate rotating in laminar flows, the immersed boundary (IB)-lattice Boltzmann (LB) method combined with the multiple-relaxation-time (MRT) collision model in two dimensions is presented. Furthermore, an implicit velocity-correction IB method is proposed to deal with the interface of moving solid boundary interacting with fluid flows. Two valuable sub-issues are particularly highlighted in the research. One is the multiple-relaxation-time immersed boundary-lattice Boltzmann (MRT-IB-LB) implementation of the fluid-structure interface enforcing the nonslip boundary condition, and the other is the effects of rotating velocities associated with aspect ratios on the plate interacting with the flows. The model is validated with the benchmark case: the flow around a cylinder asymmetrically placed in a channel. Then the effects of different rotating velocities and aspect ratios are researched. With the increasing of aspect ratios, the vortex shedding frequency increases and the multiple dominant frequencies of the hydrodynamic force occur. The formed vortices are driven downstream and amalgamated into the dominant vortices in the biased flow. The average values of hydrodynamic forces can be enlarged by increasing aspect ratio. Additionally, the drag coefficient can be decreased but the lift coefficient is increased by increasing the rotating velocity.