Unified gas-kinetic wave-particle methods V: diatomic molecular flow

10/14/2020
by   Xiaocong Xu, et al.
0

In this paper, the unified gas-kinetic wave-particle (UGKWP) method is further developed for diatomic gas with the energy exchange between translational and rotational modes for flow study in all regimes. The multiscale transport mechanism in UGKWP is coming from the direct modeling in a discretized space, where the cell's Knudsen number, defined by the ratio of particle mean free path over the numerical cell size, determines the flow physics simulated by the wave particle formulation. The non-equilibrium distribution function in UGKWP is tracked by the discrete particle and analytical wave. The weights of distributed particle and wave in different regimes are controlled by the accumulating evolution solution of particle transport and collision within a time step, where distinguishable macroscopic flow variables of particle and wave are updated inside each control volume. With the variation of local cell's Knudsen number, the UGKWP becomes a particle method in the highly rarefied flow regime and converges to the gas-kinetic scheme (GKS) for the Navier-Stokes solution in the continuum flow regime without particles. Even targeting on the same solution as the discrete velocity method (DVM)-based unified gas-kinetic scheme (UGKS), the computational cost and memory requirement in UGKWP could be reduced by several orders of magnitude for the high speed and high temperature flow simulation, where the translational and rotational non-equilibrium becomes important in the transition and rarefied regime. As a result, 3D hypersonic computations around a flying vehicle in all regimes can be conducted using a personal computer. The UGKWP method for diatomic gas will be validated in various cases from one dimensional shock structure to three dimensional flow over a sphere, and the numerical solutions will be compared with the reference DSMC results and experimental measurements.

READ FULL TEXT

page 25

page 27

page 29

page 30

page 31

page 35

07/26/2020

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

In this paper, the unified gas-kinetic wave-particle (UGKWP) method has ...
05/16/2019

A multi-prediction implicit scheme for steady state solutions of gas flow in all flow regimes

An implicit multiscale method with multiple macroscopic prediction for s...
05/26/2020

A Unified Gas-kinetic Scheme for Micro Flow Simulation Based on Linearized Kinetic Equation

The flow regime of micro flow varies from collisionless regime to hydrod...
05/12/2020

Non-equilibrium transport of inhomogeneous shale gas under ultra-tight confinement

The non-equilibrium transport of inhomogeneous and dense gases highly co...
07/26/2022

Computational Assessment of Biomass Dust Explosions in the 20L Sphere

Determination of the explosion severity parameters of biomass is crucial...
03/15/2020

Inference of Gas-liquid Flowrate using Neural Networks

The metering of gas-liquid flows is difficult due to the non-linear rela...