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Related papers: Unified Gas-Kinetic Scheme for Unsteady Multiscale…

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The unified gas-kinetic scheme (UGKS) is a direct modeling method for multiple scale transports. The modeling scale of the scheme is the mesh size and time step, and the ratios of the mesh size over particle mean free path or the time step…

Computational Physics · Physics 2019-05-01 Yajun Zhu , Chengwen Zhong , Kun Xu

In this paper, a unified gas-kinetic scheme (UGKS) with simplified multi-scale numerical flux is proposed for the thermodynamic non-equilibrium flow simulation involving the excitation of molecular vibrational degrees of freedom in all flow…

Fluid Dynamics · Physics 2023-02-08 Rui Zhang , Sha Liu , Chengwen Zhong , Congshan Zhuo

The flow regime of micro flow varies from collisionless regime to hydrodynamic regime according to the Knudsen number. On the kinetic scale, the dynamics of micro flow can be described by the linearized kinetic equation. In the continuum…

Computational Physics · Physics 2020-05-27 Chang Liu , Kun Xu

The gas dynamics under gravitational field is usually associated with the multiple scale nature due to large density variation and a wide range of local Knudsen number. It is chal- lenging to construct a reliable numerical algorithm to…

Computational Physics · Physics 2017-02-01 Tianbai Xiao , Qingdong Cai , Kun Xu

The unified gas kinetic scheme (UGKS) is a direct modeling method based on the gas dynamical model on the mesh size and time step scales. With the implementation of particle transport and collision in a time-dependent flux function, the…

Computational Physics · Physics 2017-10-25 Yajun Zhu , Chengwen Zhong , Kun Xu

In this paper, a unified gas kinetic scheme for multiphase dilute gas-particle system is proposed. The UGKS multiphase (UGKS-M) is a finite volume method, which captures flow physics in the regimes from collisionless multispecies transport…

Computational Physics · Physics 2019-05-01 Chang Liu , Zhao Wang , Kun Xu

A unified gas kinetic scheme (UGKS) for multi-scale and multi-component plasma transport is constructed. The current scheme is a direct modeling method, where the time evolution solutions from the Vlasov-BGK equations of electron and ion…

Computational Physics · Physics 2017-12-21 Chang Liu , Kun Xu

Fluid dynamic equations are valid in their respective modeling scales. With a variation of the modeling scales, theoretically there should have a continuous spectrum of fluid dynamic equations. In order to study multiscale flow evolution…

Numerical Analysis · Mathematics 2017-12-21 Chang Liu , Kun Xu , Quanhua Sun , Qingdong Cai

Reactive flows for rarefied gas mixtures involve a multi-scale transport characterized by particle collisions and free streaming, and non-equilibrium physics containing multi-species interactions, and chemical non-equilibrium. These flows…

Fluid Dynamics · Physics 2024-12-16 Yufeng Wei , Junzhe Cao , Kun Xu

The discrete unified gas kinetic scheme (DUGKS) is a finite-volume scheme with discretization of particle velocity space, which combines the advantages of both lattice Boltzmann equation (LBE) method and unified gas kinetic scheme (UGKS)…

Fluid Dynamics · Physics 2014-11-25 Chen Wu , Baochang Shi , Zhenhua Chai , Peng Wang

The unified gas-kinetic scheme (UGKS) provides a framework for simulating multiscale transport with the updates of both gas distribution function and macroscopic flow variables on the cell size and time step scales. The multiscale dynamics…

Numerical Analysis · Mathematics 2018-11-20 Chang Liu , Yajun Zhu , Kun Xu

Multiscale non-equilibrium physics at large variations of local Knudsen number are encountered in applications of aerospace engineering and micro-electro-mechanical systems, such as high-speed flying vehicles and low pressure of the…

Fluid Dynamics · Physics 2023-12-06 Yufeng Wei , Wenpei Long , Kun Xu

This paper presents a comprehensive numerical framework for simulating radiation-plasma systems. The radiative transfer process spans multiple flow regimes due to varying fluid opacity across different regions, necessitating a robust…

Astrophysics of Galaxies · Physics 2025-12-24 Mingyu Quan , Kun Xu

This paper aims at the simulation of multiple scale physics in the system of radiation hydrodynamics. The system couples the fluid dynamic evolution equations with the radiative heat transfer. The coupled system is solved by the gas-kinetic…

Computational Physics · Physics 2019-09-12 Wenjun Sun , Song Jiang , Kun Xu , Guiyu Cao

Rarefied gas effects are of critical importance for the aerodynamic performance of hypersonic vehicles operating at high altitudes. In these scenarios, conventional computational fluid dynamics (CFD) solvers break down as the linear…

Fluid Dynamics · Physics 2026-05-25 Wenpei Long , Junzhe Cao , Yue Zhang , Kun Xu

The recently proposed discrete unified gas kinetic scheme (DUGKS) is a finite volume method for deterministic solution of the Boltzmann model equation with asymptotic preserving property. In DUGKS, the numerical flux of the distribution…

Fluid Dynamics · Physics 2015-03-26 Lianhua Zhu , Zhaoli Guo , Kun Xu

In this paper, a unified gas kinetic scheme with adaptive velocity space (AUGKS) for multiscale flow transport will be developed. In near-equilibrium flow regions, particle distribution function is close to the Chapman-Enskog expansion and…

Computational Physics · Physics 2018-02-15 Tianbai Xiao , Kun Xu , Qingdong Cai

The discrete unified gas kinetic scheme (DUGKS) is a new finite volume (FV) scheme for continuum and rarefied flows which combines the benefits of both Lattice Boltzmann Method (LBM) and unified gas kinetic scheme (UGKS). By reconstruction…

Computational Physics · Physics 2024-05-29 Mingliang Zhong , Sen Zou , Dongxin Pan , Congshan Zhuo , Chengwen Zhong

The Gas-Kinetic Scheme (GKS), widely used in computational fluid dynamics for simulating hypersonic and other complicated flow phenomena, is extended in this work to electromagnetic problems by solving Maxwell's equations. In contrast to…

Numerical Analysis · Mathematics 2026-01-01 Zhigang Pu , Wenpei Long , Kun Xu

In this paper, we present an advanced high-order compact gas-kinetic scheme (CGKS) for 3D unstructured mixed-element meshes, augmented with a geometric multigrid technique to accelerate steady-state convergence. The scheme evolves…

Computational Physics · Physics 2024-02-06 Hongyu Liu , Xing Ji , Yunpeng Mao , Yuan Ding , Kun Xu
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