An immersed boundary method‐discrete unified gas kinetic scheme simulation of particle‐laden turbulent channel flow on a nonuniform orthogonal mesh

Particle‐resolved simulations of turbulent particle‐laden flows provide a powerful research tool to explore detailed flow physics at all scales. However, efficient particle‐resolved simulations for wall‐bounded turbulent particle‐laden flows remain a challenging task. In this article, we develop a simulation approach for a turbulent channel flow laden with finite‐size particles on a nonuniform mesh by combining the discrete unified gas kinetic scheme (DUGKS) and the immersed boundary method (IBM). The standard discrete delta function was modified according to reproducible kernel particle method to take into account mesh non‐uniformity and correctly conserve force moments. Simulation results based on uniform and nonuniform meshes are compared to validate and examine the accuracy of the nonuniform mesh DUGKS‐IBM. Finally, the computational performance of the nonuniform mesh DUGKS‐IBM is discussed. Application of a nonuniform mesh IBM can significantly reduce the mesh requirement for particle‐laden turbulent channel flow simulation while being capable of better resolving the near‐wall small‐scale flow dynamics. Nonuniform mesh simulations, while with a reduction of the CPU time by a factor of more than 7, are shown to provide comparable results as those based on a uniform mesh. The effects of finite‐size solid particles on the mean flow velocity, Reynolds stress, and root‐mean‐squared velocity fluctuations are presented, to demonstrate various aspects of turbulence modulation by solid particles.