Work

A multiscale Boltzmann equation for complex systems of neutral gases across all flow regimes

Year: 2025

Type: article

Abstract: A multiscale Boltzmann equation (MBE) is found from the gas-kinetic theory as the master equation for complex physical systems of neutral gases across all flow regimes, which span from the continuum limit to the free-molecular limit, covering a vast range of applications such as hypersonic flows over near-space vehicles and delicate flows around micro-electromechanical systems. A key feature of this MBE is the introduction of the observation scale into the master equation, which distinguishes the MBE from single-scale master (or governing) equations where fixed observation scales are implied in their basic assumptions. The fundamental properties of MBE, such as the asymptotic preserving property, are proved theoretically, and a concise numerical scheme is developed for MBE to demonstrate its validity on benchmark multiscale problems.

Source: Physics of Fluids

DOI: 10.1063/5.0290838

Authors: Sha Liu, Junzhe Cao, Sirui Yang, Chengwen Zhong

Institution: Northwestern Polytechnical University

Language: English

Topic: Gas Dynamics and Kinetic Theory

Subfield: Applied Mathematics

Field: Mathematics

Domain: Physical Sciences

Open Access status: green

Funder: National Natural Science Foundation of China

Awards: RCS喷流对高超声速稀薄来流的流动干扰研究, G6762898385