检索结果-南通市图书馆

Solving coupled nonlinear Schrödinger equations via a direct discontinuous galerkin method

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2012年第3期21卷 10-14页

作者：张荣培蔚喜军冯涛 School of Sciences Liaoning Shihua University Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics

In this work,we present the direct discontinuous galerkin(DDG) method for the one-dimensional coupled nonlinear Schrdinger(CNLS) *** prove that the new discontinuous galerkin method preserves the discrete mass conservations corresponding to the properties of the CNLS *** ordinary differential equations obtained by the DDG space discretization is solved via a third-order stabilized Runge-Kutta *** experiments show that the new DDG scheme gives stable and less diffusive results and has excellent long-time numerical behaviors for the CNLS equations.

关键词： direct discontinuous galerkin method coupled nonlinear Schrdinger equation mass conservation

A direct discontinuous galerkin method with Interface Correction for the Compressible Navier-Stokes Equations on Unstructured Grids

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Advances in Applied Mathematics and Mechanics 2018年第1期10卷 1-21页

作者： Jian Cheng Huiqiang Yue Shengjiao Yu Tiegang Liu School of Mathematics and Systems Science Beihang UniversityBeijing 100091China

Since the original DDG method has been introduced by Liu et al.[8]in 2009,a variety of DDG type methods have been proposed and further *** this paper,we further investigate and develop a new DDG method with interface correction(DDG(IC))as the discretization of viscous and heat fluxes for the compressible Navier-Stokes equations on unstructured *** to the original DDG method,the newly developed DDG(IC)method demonstrates its superior in delivering the optimal order of accuracy under demanding *** in extension and application of this newly developed DDG(IC)method for solving the compressible Navier-Stokes equations and special treatments designed for handling boundary viscous fluxes are presented and examined in this *** performance of the new DDG method with interface correction is carefully evaluated and assessed through a number of typical test *** experiments show that the new DDG method with interface correction can achieve the optimal order of accuracy on both uniform structured grids and nonuniform unstructured grids,which clearly indicates its potential for further applications of real engineering practices.

关键词： direct discontinuous galerkin method high-order method compressible Navier-Stokes equations

A High-Order direct discontinuous galerkin method for Variable Density Incompressible Flows

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2022年第8期32卷 850-877页

作者： Fan Zhang Tiegang Liu School of Mathematics and Physics University of Science and Technology BeijingBeijing 100083P.R.China School of Mathematics Beihang UniversityBeijing 100191P.R.China

In this work,we develop a novel high-order discontinuous galerkin(DG)method for solving the incompressible Navier-Stokes equations with variable *** incompressibility constraint at cell interfaces is relaxed by an artificial compressibility ***,since the hyperbolic nature of the governing equations is recovered,the simple and robust Harten-Lax-van Leer(HLL)flux is applied to discrete the inviscid term of the variable density incompressible Navier-Stokes *** viscous term is discretized by the direct DG(DDG)method,the construction of which was initially inspired by the weak solution of a scalar diffusion *** addition,in order to eliminate the spurious oscillations around sharp density gradients,a local slope limiting operator is also applied during the highly stratified flow *** convergence property and performance of the present high-order DDG method are well demonstrated by several benchmark and challenging numerical test *** to its advantages of simplicity and robustness in implementation,the present method offers an effective approach for simulating the variable density incompressible flows.

关键词： Variable density incompressible flows direct discontinuous galerkin method artificial compressibility high-order accuracy

The direct discontinuous galerkin methods with Implicit-Explicit Runge-Kutta Time Marching for Linear Convection-Diffusion Problems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications on Applied Mathematics and Computation 2022年第1期4卷 271-292页

作者： Haijin Wang Qiang Zhang School of Science Nanjing University of Posts and TelecommunicationsNanjing 210023China Department of Mathematics Nanjing UniversityNanjing 210093China

In this paper,a fully discrete stability analysis is carried out for the direct discontinuous galerkin(DDG)methods coupled with Runge-Kutta-type implicit-explicit time marching,for solving one-dimensional linear convection-diffusion *** the spatial discretization,both the original DDG methods and the refined DDG methods with interface corrections are *** the time discretization,the convection term is treated explicitly and the diffusion term *** the energy method,we show that the corresponding fully discrete schemes are unconditionally stable,in the sense that the time-stepis only required to be upper bounded by a constant which is independent of the mesh size ***-mal error estimate is also obtained by the aid of a special global *** experiments are given to verify the stability and accuracy of the proposed schemes.

关键词： direct discontinuous galerkin method Implicit-explicit scheme Stability analysis Energy method Convection-diffusion problem

Solution Remapping method with Lower Bound Preservation for Navier-Stokes Equations in Aerodynamic Shape Optimization

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2023年第5期33卷 1381-1408页

作者： Bin Zhang Weixiong Yuan Kun Wang Jufang Wang Tiegang Liu LMIB and School of Mathematical Sciences Beihang UniversityBeijing 100191China Computational Aerodynamic Research Institute China Aerodynamics Research and Development CenterMianyang 621000China

It is found that the solution remapping technique proposed in[***.,2020,13(4)]and[***.,2021,87(3):1-26]does not work out for the Navier-Stokes equations with a high Reynolds *** shape deformations usually reach several boundary layer mesh sizes for viscous flow,which far exceed one-layer mesh that the original method can *** direct application to Navier-Stokes equations can result in the unphysical pressures in remapped solutions,even though the conservative variables are within the reasonable *** this work,a new solution remapping technique with lower bound preservation is proposed to construct initial values for the new shapes,and the global minimum density and pressure of the current shape which serve as lower bounds of the corresponding variables are used to constrain the remapped *** solution distribution provided by the present method is proven to be acceptable as an initial value for the new *** numerical experiments show that the present technique can substantially accelerate the flow convergence for large deformation problemswith 70%-80%CPU time reduction in the viscous airfoil drag minimization.

关键词： Aerodynamic shape optimization solution remapping technique direct discontinuous galerkin method lower bound preservation Navier-Stokes equations