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Related papers: Compact Higher-order Gas-kinetic Schemes with Spec…

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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 gas-kinetic scheme (GKS) provides high computational efficiency and accuracy for continuum flow simulations but is unable to reliably capture rarefaction effects. In contrast, although the discrete velocity method (DVM) is better suited…

Fluid Dynamics · Physics 2026-05-08 Hangkong Wu , Yuze Zhu , Yajun Zhu , Kun Xu

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

For increasingly rarefied flowfields, the Navier-Stokes (NS) equations lose accuracy partially due to the single temperature approximation. To overcome this barrier, a continuum multi-temperature model based on the Bhatnagar-Gross-Krook…

Fluid Dynamics · Physics 2018-10-12 Guiyu Cao , Hualin Liu , Kun Xu

There have been great efforts on the development of higher-order numerical schemes for compressible Euler equations. The traditional tests mostly targeting on the strong shock interactions alone may not be adequate to test the performance…

Numerical Analysis · Mathematics 2016-09-16 Liang Pan , Jiequan Li , Kun Xu

The high-order numerical solution of the non-linear shallow water equations (and of hyperbolic systems in general) is susceptible to unphysical Gibbs oscillations that form in the proximity of strong gradients. The solution to this problem…

Numerical Analysis · Mathematics 2016-07-18 Simone Marras , Michal A. Kopera , Emil M. Constantinescu , Jenny Suckale , Francis X. Giraldo

This study presents an efficient and accurate discrete adjoint gas-kinetic scheme (GKS) for sensitivity analysis and aerodynamic shape optimization in continuum flow regimes. Developed using the backward mode of algorithmic differentiation…

Fluid Dynamics · Physics 2026-04-17 Hangkong Wu , Yuze Zhu , Yajun Zhu , Kun Xu

This paper is a continuation of our earlier work [Z.L. Guo {\it et al.}, Phys. Rev. E {\bf 88}, 033305 (2013)] where a multiscale numerical scheme based on kinetic model was developed for low speed isothermal flows with arbitrary Knudsen…

Fluid Dynamics · Physics 2015-06-22 Zhaoli Guo , Ruijie Wang , Kun Xu

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

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

Unified gas kinetic scheme (UGKS) is an asymptotic preserving scheme for the kinetic equations. It is superior for transition flow simulations, and has been validated in the past years. However, compared to the well known discrete ordinate…

Fluid Dynamics · Physics 2016-08-31 Songze Chen , Zhaoli Guo , Kun Xu

The unified gas-kinetic scheme (UGKS) is becoming increasingly popular for multiscale simulations in all flow regimes. This paper provides the first analytical study on the stability of the UGKS applied to a linear kinetic model, which is…

Numerical Analysis · Mathematics 2025-05-02 Tuowei Chen , Kun Xu

This paper presents an implicit method for the discrete unified gas-kinetic scheme (DUGKS) to speed up the simulations of the steady flows in all flow regimes. The DUGKS is a multi-scale scheme finite volume method (FVM) for all flow…

Fluid Dynamics · Physics 2018-10-18 Dongxin Pan , Chengwen Zhong , Congshan Zhuo

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

This article investigates matrix-free higher-order discontinuous Galerkin discretizations of the Navier--Stokes equations for incompressible flows with variable viscosity. The viscosity field may be prescribed analytically or governed by a…

Computational Engineering, Finance, and Science · Computer Science 2025-11-04 Richard Schussnig , Niklas Fehn , Douglas Ramalho Queiroz Pacheco , Martin Kronbichler

High-order nodal space-time flux reconstruction (STFR) methods have been developed to solve hyperbolic conservation laws on curvilinear moving grids. Unlike the method-of-lines approach for moving domain simulation, the grid velocity is…

Numerical Analysis · Mathematics 2025-11-19 Meilin Yu

The mass flow rate of Poiseuille flow of rarefied gas through long ducts of two-dimensional cross-sections with arbitrary shape are critical in the pore-network modeling of gas transport in porous media. In this paper, for the first time,…

Computational Physics · Physics 2018-11-14 Wei Su , Peng Wang , Yonghao Zhang , Lei Wu

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

Nonequilibrium flows have been frequently encountered in various aerospace engineering applications. To understand nonequilibrium physics, multiscale effects, and the dynamics in these applications, an effective and reliable multiscale…

Fluid Dynamics · Physics 2024-07-23 Wenpei Long , Yufeng Wei , Kun Xu

In this paper, a unified framework for particulate two-phase flow will be presented with a wide range of solid-particle concentration from dilute to dense limit. The two phase flow is simulated by two coupled flow solvers, i.e., the…

Fluid Dynamics · Physics 2022-02-23 Xiaojian Yang , Wei Shyy , Kun Xu