arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1910.09899math.NAcs.NA
收藏

用奇异性交换法求二维和三维近似奇异线积分的精确quadrature

Accurate quadrature of nearly singular line integrals in two and three dimensions by singularity swapping

Ludvig af Klinteberg, Alex H. Barnett

摘要:

Helsing及其同事的方法评估拉普拉斯和相关层的潜力所产生的面板(复合)正交曲线,有效地和高阶精度任意接近的目标。由于它利用了复分析,因此其使用仅限于二维(2D)。我们首先解释其损失的准确性,面板变得弯曲,使用经典的复杂的近似结果沃尔什,可以被解释为“静电屏蔽”的施瓦茨奇点。然后,我们引入了一个变种,交换目标奇点在其复杂的参数原像;在后者的空间面板是平坦的,因此收敛速度可以高得多。通过牛顿迭代法鲁棒地找到原像。这个想法也使,第一次,近奇异积分的潜力产生的平滑曲线在3D中,建立在递归的Tornberg-Gustavsson。我们应用这个精确的评估斯托克斯流附近的弯曲细丝在细长体近似。我们的3D方法比现有的唯一替代方案,即自适应集成,效率高出数倍(无论是在内核评估方面,还是在C实现中的速度方面)。

英文摘要:

The method of Helsing and co-workers evaluates Laplace and related layer potentials generated by a panel (composite) quadrature on a curve, efficiently and with high-order accuracy for arbitrarily close targets. Since it exploits complex analysis, its use has been restricted to two dimensions (2D). We first explain its loss of accuracy as panels become curved, using a classical complex approximation result of Walsh that can be interpreted as "electrostatic shielding" of a Schwarz singularity. We then introduce a variant that swaps the target singularity for one at its complexified parameter preimage; in the latter space the panel is flat, hence the convergence rate can be much higher. The preimage is found robustly by Newton iteration. This idea also enables, for the first time, a near-singular quadrature for potentials generated by smooth curves in 3D, building on recurrences of Tornberg-Gustavsson. We apply this to accurate evaluation of the Stokes flow near to a curved filament in the slender body approximation. Our 3D method is several times more efficient (both in terms of kernel evaluations, and in speed in a C implementation) than the only existing alternative, namely, adaptive integration.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑