A new method for solving convection-diffusion equation using Associated Hermite orthogonal functions
Received:October 22, 2015  Revised:December 09, 2015
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DOI:10.7511/jslx201606012
KeyWord:Hermite polynomials  unconditionally  finite difference  convection-diffusion equation  ADI
              
AuthorInstitution
张迪 解放军理工大学 国防工程学院, 南京
缪小平 解放军理工大学 国防工程学院, 南京
彭福胜 解放军理工大学 国防工程学院, 南京
江丰 解放军理工大学 国防工程学院, 南京
魏子杰 解放军理工大学 国防工程学院, 南京
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Abstract:
      In this work,an unconditionally stable method using the Associated Hermite (AH) orthogonal functions for solving the convection-diffusion equation is proposed.The time derivatives in the equation are expanded by the weighted Hermite functions.By introducing the Galerkin temporal testing procedure to the expanded equation,the time variable can be eliminated in the process of calculation.An implicit difference equation can then be obtained in AH domain under no convergent conditions.The numerical results of the equation can be obtained by solving the expanded coefficients in AH domain recursively.Two numerical examples were conducted to validate the accuracy and the efficiency of the proposed method by comparing to the conventional finite difference method and the alternating direction implicit (ADI) method.The numerical results have shown that the accuracy of this unconditionally stable method is independent of the time step size,and this proposed method has great advantage in efficiency in a computational domain with fine structure in convection-diffusion problems.Moreover,the agreement between the results obtained using the FD method and the proposed method is very good.