对边界元法的改进（Ⅱ）

Improvements on the Boundary Element Method(Ⅱ)

就传统边界元法在计算靠近边界的内点位（或场分量）值方面所存在的问题。提出了一种改进方法，即边界单元外移法，它将距所求内点最近的边界单元外移一适当距离，以减小基本解奇异性对求解稳定性和精度的不良影响。推导了外移单元上等效源密度的计算公式，给出了一个算例。

The tranditional boundary element method has some drawbacks when used tocompute the potentials or the components of the vector field of the internal points near the bound-ary. The paper presents an improved method──the boundary element outward-moving method,which moves the closest boundary element to the internal point outward to a suitable distance , in or-der to reduce the ill influences on the numerical stabilitv and accuracy caused by the singularity ofthe fundamental solution. And the formula of the equivalent source density on the outward-movingboundary elemennt is deduced with an example.