From the point of view of energy analysis, the cause that the uniqueness of the boundary integral equation induced from the exterior Helmholtz problem does not hold is investigated in this paper. It is proved that the...From the point of view of energy analysis, the cause that the uniqueness of the boundary integral equation induced from the exterior Helmholtz problem does not hold is investigated in this paper. It is proved that the Sommerfeld's condition at the infinity is changed so that it is suitable not only for the radiative wave but also for the absorptive wave when we use the boundary integral equation to describe the exterior Helmholtz problem. There fore, the total energy of the system is conservative. The mathematical dealings to guarantee the uniqueness are discussed based upon this explanation.展开更多
In this paper we consider a kind of exterior transmission problem in which the refractive index n（x） is a piecewise positive constant. Through establishing an equivalent boundary integral system, we obtain that the ...In this paper we consider a kind of exterior transmission problem in which the refractive index n（x） is a piecewise positive constant. Through establishing an equivalent boundary integral system, we obtain that the set of exterior transmission eigenvalues is a discrete set. Furthermore, we prove that there does not exist a transmission eigenvalue under some conditions.展开更多
There are two cases of the exterior problems of the Helmholtz equation. If λ ≥ 0 the bilinear form is coercive, and if λ < 0 it is the scattering problem. We give a new approach of the infinite element method, w...There are two cases of the exterior problems of the Helmholtz equation. If λ ≥ 0 the bilinear form is coercive, and if λ < 0 it is the scattering problem. We give a new approach of the infinite element method, which enables us to solve these exterior problems as well as corner problems. A numerical example of the scattering problem is given. [ABSTRACT FROM AUTHOR]展开更多
In this paper,we investigate the method of fundamental solutions(MFS)for solving exterior Helmholtz problems with high wave-number in axisymmetric domains.Since the coefficientmatrix in the linear system resulting fro...In this paper,we investigate the method of fundamental solutions(MFS)for solving exterior Helmholtz problems with high wave-number in axisymmetric domains.Since the coefficientmatrix in the linear system resulting fromtheMFS approximation has a block circulant structure,it can be solved by the matrix decomposition algorithm and fast Fourier transform for the fast computation of large-scale problems and meanwhile saving computer memory space.Several numerical examples are provided to demonstrate its applicability and efficacy in two and three dimensional domains.展开更多
In this Paper, a coupled natural boundary-finite element method is presented for solving three-dimensional Helmholtz equation in an unbounded domain.The existence and uniqueness of the solution for both continuous and...In this Paper, a coupled natural boundary-finite element method is presented for solving three-dimensional Helmholtz equation in an unbounded domain.The existence and uniqueness of the solution for both continuous and discrete problems are studied.Error estimated and some numerical results are given.展开更多
文摘From the point of view of energy analysis, the cause that the uniqueness of the boundary integral equation induced from the exterior Helmholtz problem does not hold is investigated in this paper. It is proved that the Sommerfeld's condition at the infinity is changed so that it is suitable not only for the radiative wave but also for the absorptive wave when we use the boundary integral equation to describe the exterior Helmholtz problem. There fore, the total energy of the system is conservative. The mathematical dealings to guarantee the uniqueness are discussed based upon this explanation.
基金supported by National Natural Science Foundation of People’s Republic of China(11571132 and 11171127)Supported in Part by Program for Changjiang Scholars and Innovative Research Team in University No.IRT13066
文摘In this paper we consider a kind of exterior transmission problem in which the refractive index n（x） is a piecewise positive constant. Through establishing an equivalent boundary integral system, we obtain that the set of exterior transmission eigenvalues is a discrete set. Furthermore, we prove that there does not exist a transmission eigenvalue under some conditions.
基金the China State Major Key Project for Basic Researches and the Science Fund of the Ministry of Education of China.
文摘There are two cases of the exterior problems of the Helmholtz equation. If λ ≥ 0 the bilinear form is coercive, and if λ < 0 it is the scattering problem. We give a new approach of the infinite element method, which enables us to solve these exterior problems as well as corner problems. A numerical example of the scattering problem is given. [ABSTRACT FROM AUTHOR]
基金The work described in this paper was supported by National Basic Research Program of China(973 Project No.2010CB832702)the R&D Special Fund for Public Welfare Industry(Hydrodynamics,Project No.201101014 and the 111 project under grant B12032)National Science Funds for Distinguished Young Scholars(Grant No.11125208).The third author acknowledges the support of Distinguished Overseas Visiting Scholar Fellowship provided by the Ministry of Education of China.
文摘In this paper,we investigate the method of fundamental solutions(MFS)for solving exterior Helmholtz problems with high wave-number in axisymmetric domains.Since the coefficientmatrix in the linear system resulting fromtheMFS approximation has a block circulant structure,it can be solved by the matrix decomposition algorithm and fast Fourier transform for the fast computation of large-scale problems and meanwhile saving computer memory space.Several numerical examples are provided to demonstrate its applicability and efficacy in two and three dimensional domains.
文摘In this Paper, a coupled natural boundary-finite element method is presented for solving three-dimensional Helmholtz equation in an unbounded domain.The existence and uniqueness of the solution for both continuous and discrete problems are studied.Error estimated and some numerical results are given.
