Special issue on recent hot topics in rarefied gas dynamics

Rarefied gas flows are present in a wide range of scientific and technological problems, such as hypersonic vehicles flying at very high altitudes, propulsion systems of spacecraft navigating in space, and vacuum devices operating on the ground. To continue engagement in the rarefied gas dynamics (RGD) community and bring together researchers, the 'Pre-RGD32 Online Workshop on Recent Hot Topics in Rarefied Gas Dynamics' was held during July 7-10th, 2021. This special issue presents a selection of papers from the workshop, highlighting works of innovative CFD research and developments of a fundamental or applied nature, and their applications to the field of rarefied gas dynamics.