位势问题边界元法中几乎奇异积分的正则化

将一种通用算法应用于平面位势问题边界元法中近边界点几乎奇异积分的正则化。对线性单元,位势问题近边界点的几乎强和超奇异积分可归纳为两种形式。通过分部积分,将引起奇异的积分元素变换到积分号之外,从而对这两种积分分别给出了无奇异的正则化计算公式。除了线性元,二次元也应用于该算法。与近边界点临近的二次单元划分为两段线性单元,该算法仍然适用。算例证明了方法的有效性和精确性。对曲线边界问题,联合二次元和线性元可提高计算结果精确度。

Regularization of Nearly Singular Integrals in the Boundary Element Method of Potential Problems

A general algorithm is applied to the regularization of nearly singular integrals in the boundary element method of planar potential problems.For linear elements,the strongly singular and hypersingular integrals of the interior points very close to boundary were categorized into two forms. The factor leading to the singularity was transformed out of the integral representations with integration by parts,so non-singular regularized formulas were presented for the two forms of integrals.Furthermore,quadratic elements are used in addition to linear ones.The quadratic element very close to the internal point can be divided into two linear ones,so that the algorithm is still valid.Numerical examples demonstrate the effectiveness and accuracy of this algorithm.Especially for problems with curved boundaries,the combination of quadratic elements and linear elements can give more accurate results.