Hunan Key Laboratory for Computation and Simulation in Science and Engineering

Hunan, China

Hunan Key Laboratory for Computation and Simulation in Science and Engineering

Hunan, China

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Xu J.-J.,Xiangtan University | Xu J.-J.,Hunan Key Laboratory for Computation and Simulation in Science and Engineering | Huang Y.,Xiangtan University | Huang Y.,Hunan Key Laboratory for Computation and Simulation in Science and Engineering | And 3 more authors.
Communications in Computational Physics | Year: 2014

In this paper, a numericalmethod is presented for simulating the 3D interfacial flows with insoluble surfactant. The numerical scheme consists of a 3D immersed interface method (IIM) for solving Stokes equations with jumps across the interface and a 3D level-set method for solving the surfactant convection-diffusion equation along a moving and deforming interface. The 3D IIM Poisson solver modifies the one in the literature by assuming that the jump conditions of the solution and the flux are implicitly given at the grid points in a small neighborhood of the interface. This assumption is convenient in conjunction with the level-set techniques. It allows standard Lagrangian interpolation for quantities at the projection points on the interface. The interface jump relations are re-derived accordingly. A novel rotational procedure is given to generate smooth local coordinate systems and make effective interpolation. Numerical examples demonstrate that the IIM Poisson solver and the Stokes solver achieve second-order accuracy. A 3D drop with insoluble surfactant under shear flow is investigated numerically by studying the influences of different physical parameters on the drop deformation. ©2014 Global-Science Press.


Ma J.,Xiangtan University | Li M.,Xiangtan University | Li M.,Hunan Key Laboratory for Computation and Simulation in Science and Engineering | Zhang Y.,Xiangtan University | Zhou H.,Xiangtan University
Communications in Computer and Information Science | Year: 2014

A kind of equal-task multiple traveling salesman problem (ET-mTSP) was proposed based on the mTSP and its corresponding mathematical model was constructed; Then, a series of discrete operations for firefly algorithm (FA) were conducted to solve this problem; Finally, the results and analysis of experiments showed that the improved algorithm was efficient and suitable for solving such ET-mTSP. © Springer-Verlag Berlin Heidelberg 2014.


Xu J.-J.,Xiangtan University | Xu J.-J.,Hunan Key Laboratory for Computation and Simulation in Science and Engineering | Yang Y.,Xiangtan University | Yang Y.,Hunan Key Laboratory for Computation and Simulation in Science and Engineering | Lowengrub J.,University of California at Irvine
Journal of Computational Physics | Year: 2012

A level-set continuum surface force method is presented to compute two-phase flows with insoluble surfactant. Our method recasts the Navier-Stokes equations for a two-phase flow with insoluble surfactant as " one-fluid" formulation. Interfacial transport and interfacial jump conditions are treated using the level-set method and the discrete Dirac function. Based on the density-weighted projection method, a stable semi-implicit scheme is used to decouple the velocity components in solving the regularized Navier-Stokes equations. It allows numerical simulations for a wide range of viscosity ratios and density ratios.Numerical simulations on single drop deformation in a 2D shear flow are presented. Simulations on two drop interaction shows that surfactants can play a critical role in preventing drop coalescence. A fully 3D simulation demonstrating the physical interactions of multiple surfactant-laden drops is presented. © 2012 Elsevier Inc.


Zhou G.M.,Xiangtan University | Zhou G.M.,Hunan Key Laboratory for Computation and Simulation in Science and Engineering | Deng C.,Xiangtan University | Wu K.,Xiangtan University
Advances in Applied Mathematics and Mechanics | Year: 2016

In this paper, semidefinite optimization method is proposed to estimate bounds on linear functionals defined on solutions of linear ordinary differential equations (ODEs) with smooth coefficients. The method can get upper and lower bounds by solving two semidefinite programs, not solving ODEs directly. Its convergence theorem is proved. The theorem shows that the upper and lower bounds series of linear functionals discussed can approach their exact values infinitely. Numerical results show that the method is effective for the estimation problems discussed. In addition, in order to reduce calculation amount, Cheybeshev polynomials are applied to replace Taylor polynomials of smooth coefficients in computing process. © 2016 Global Science Press.


Li M.,Xiangtan University | Li M.,Hunan Key Laboratory for Computation and Simulation in Science and Engineering | Ma J.,Xiangtan University | Zhang Y.,Xiangtan University | And 2 more authors.
Journal of Computational and Theoretical Nanoscience | Year: 2015

The multiple traveling salesman problem (mTSP) is a generalization of the well-known traveling salesman problem (TSP), where more than one salesman is allowed to be used in the solution. Firstly, a kind of equal-task multiple traveling salesman problem (ET-mTSP) was proposed and its corresponding mathematical model was constructed; secondly, firefly algorithm was introduced to solve this problem, and a series of discrete operations were conducted to adapt to it. Standard firefly algorithm was improved to be discrete firefly algorithm, also the general methods and steps were presented to solve the ET-mTSP. And the algorithm had a good performance for solving ET-mTSP. The performance of FA is significantly better than GA for solving such ET-mTSP. Copyright © 2015 American Scientific Publishers.


Wen L.,Xiangtan University | Wen L.,Hunan Key Laboratory for Computation and Simulation in Science and Engineering | Liu X.,Xiangtan University
BIT Numerical Mathematics | Year: 2012

This paper is concerned with the analytic and numerical stability of a class of nonlinear neutral delay differential equations. A sufficient condition for the stability of the problems itself is given. The numerical stability results are obtained for A-stable one-leg methods when they are applied to above mentioned problems. Numerical examples are given to confirm our theoretical results. © 2011 Springer Science + Business Media B.V.

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