Kinetic representation of the unified gas-kinetic wave-particle method and beyond

TL;DR

This paper revisits the kinetic foundations of the UGKWP method, presenting a new kinetic system that decomposes the original equation, enabling the development of advanced multiscale flow simulation techniques.

Contribution

It introduces a kinetic system based on collision decomposition of the UGKWP method, providing a new theoretical basis for multiscale flow modeling.

Findings

Kinetic equations for wave and particle components are derived.

The kinetic system offers a new perspective for flow regime modeling.

Potential for developing new kinetic methods for all flow regimes.

Abstract

The unified gas-kinetic wave-particle (UGKWP) method is a hybrid method for multiscale flow simulations, in which the contributions to the whole gas evolution from deterministic hydrodynamic wave and stochastic particle transport are combined simultaneously. Originally, the UGKWP method was developed as a direct modeling approach at discrete level. In this work, we revisit the time evolution of each part of the involved simulation particles and wave molecules in UGKWP, and present the corresponding kinetic equations. The resultant kinetic system can be viewed as a collision decomposition of the original kinetic equation, which can serve as a basis for developing other kinetic methods for flows in all flow regimes.