A three-dimensional unified gas-kinetic wave-particle solver for flow computation in all regimes

TL;DR

This paper introduces a 3D unified gas-kinetic wave-particle (UGKWP) method that efficiently simulates multiscale flows across all regimes using a wave-particle approach on unstructured meshes, validated by various complex flow cases.

Contribution

The paper presents a novel 3D UGKWP method combining wave and particle models for multiscale flow simulation, enabling efficient and accurate analysis across different flow regimes.

Findings

Validated on multiple 3D flow cases with varying Mach and Knudsen numbers.

Achieved good parallel performance on supercomputers.

Effectively captures continuum and rarefied flow interactions.

Abstract

In this paper, the unified gas-kinetic wave-particle (UGKWP) method has been constructed on three-dimensional unstructured mesh with parallel computing for multiscale flow simulation. Following the direct modeling methodology of the unified gas-kinetic scheme (UGKS), the UGKWP method models the flow dynamics uniformly in different regime and gets the local cell's Knudsen number dependent numerical solution directly without the requirement of kinetic scale cell resolution. The UGKWP method is composed of evolution of deterministic wave and stochastic particles. With the dynamic wave-particle decomposition, the UGKWP method is able to capture the continuum wave interaction and rarefied particle transport under a unified framework and achieves the high efficiency in different flow regime. The UGKWP flow solver is validated by many three-dimensional test cases of different Mach and Knudsen numbers, which include 3D shock tube problem, lid-driven cavity flow, high-speed flow passing through a cubic object, and hypersonic flow around a space vehicle. The parallel performance has been tested on the Tianhe-2 supercomputer, and reasonable parallel performance has been observed up to one thousand core processing. Due to wave-particle formulation, the UGKWP method has great potential in solving three-dimensional multiscale transport with the co-existence of continuum and rarefied flow regimes, especially for the high-speed rarefied and continuum flow around space vehicle in near space flight.