子波变换在声辐射和声散射数值解中的应用
On the use of wavelet transform for the integral-equation solution of acoustic radiation and scattering
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摘要: 通过将边界变量用于波展开,获得了求解二维及三维轴对称声辐射和声散射的边界积分方程的子波谱方法,既可求解Dirichlet、Neumann问题,也可求解混合过值问题;它能处理任意边界条件的油对称体.用三维元方法解决了三维轴对称问题边界于波谱方法的奇异积分。给出了二维问题奇异积分的近似积分公式。给出了子波谱方法的系数计算方法,它与传统的边界元系数计算方法相似,易于计算机程序实现,能处理复杂的边界几何形状。该方法的优点是可以获得稀疏的系数矩阵。算例表明:该方法收敛较快,精度高。Abstract: In present integral equation methods for acoustic problems, a full matrix equation whose solution has a high computational cost is usually resulted. In this paper, a new wavelet approach is presented for efficient solution of the two-dimensional and axisymmetric acoustic radiation and scattering problems with arbitrary boundary conditions. On the basis of two-dimensional and axisyrmmetric iategral equations, the boundary quantities are expanded in terms of orthogonal or periodic, orthogonal wavelet basis functions and the geometrical representation of the Boundary Element Method is employed to treat the curved computational domain. The approximate analytical formulation deals directly with the singularities for two-dimensional problems and the singular integrals are computed directly by employing highly accurate three-dimensional integration techniques for axisyrnmetric problems. The advantages of the new approach are a highly sparse matrix system which can be solved rapidly by sparse solvers and accurately modeling of curve surface. The results from the new approach are compared with the BEM, the analytical solutions, which demonstrate that the new technique has fast convergence and good accuracy.