A sharp interface immersed boundary-discrete unified gas kinetic scheme for fluid-solid flows with heat transfer

Particulate flow with thermal convection involves lots of moving and complex fluid-solid interfaces, and hence generally sheets a great challenge to numerical methods. For interface-resolved simulation of that flow, we present a ghost-cell (GC) method in the framework of discrete unified gas kinetic scheme (DUGKS) in this study. As a sharp interface immersed boundary model, the particle surface is considered to be of zero thickness in GC. A computation cell with its center located inside the particle and intersected by the interface is transformed into the fictitious cell, and its information is reconstructed from neighboring fields. The fluid motion with heat transfer is solved by the recently proposed DUGKS. For updating the position of particles, we evaluate the hydrodynamic forces of fluid-solid interaction through the mesoscopic momentum flux. The particle-particle interaction is described by the repulsive force model. The accuracy of the method is corroborated by five benchmark cases of flow past a heated cylinder, sedimentation of a cold particle in a channel, a catalyst particle migrating in a box, drafting-kissing-tumbling process of two hot particles, and a group of particles settling in an enclosure. It is observed that GC-DUGKS well captures the character of the thermal particulate flows.