A Cartesian Cut Cell Method for Rarefied Flow Simulations around Moving Obstacles
For researchers simulating rarefied gas flows with moving obstacles, this method simplifies implementation and enables 3D simulations, but it is an incremental improvement over existing cut cell methods.
The paper proposes a Cartesian cut cell method for rarefied gas flow simulations around moving obstacles, achieving exact conservation and accurate boundary treatment. It demonstrates the method on several test cases, including a 3D unsteady Crookes radiometer simulation.
For accurate simulations of rarefied gas flows around moving obstacles, we propose a cut cell method on Cartesian grids: it allows exact conservation and accurate treatment of boundary conditions. Our approach is designed to treat Cartesian cells and various kind of cut cells by the same algorithm, with no need to identify the specific shape of each cut cell. This makes the implementation quite simple, and allows a direct extension to 3D problems. Such simulations are also made possible by using an adaptive mesh refinement technique and a hybrid parallel implementation. This is illustrated by several test cases, including a 3D unsteady simulation of the Crookes radiometer.