New hybrid quadrature schemes for weakly singular kernels applied to isogeometric boundary elements for 3D Stokes flow

Maximilian Harmel; Roger Sauer

doi:10.1016/j.enganabound.2023.04.037

New hybrid quadrature schemes for weakly singular kernels applied to isogeometric boundary elements for 3D Stokes flow

Abstract

This work proposes four novel hybrid quadrature schemes for the efficient and accurate evaluation of weakly singular boundary integrals (1/r kernel) on arbitrary smooth surfaces. Such integrals appear in boundary element analysis for several partial differential equations including the Stokes equation for viscous flow and the Helmholtz equation for acoustics. The proposed quadrature schemes apply a Duffy transform-based quadrature rule (Duffy, 1982) to surface elements containing the singularity and classical Gaussian quadrature to the remaining elements. Two of the four schemes additionally consider a special treatment for elements near to the singularity, where refined Gaussian quadrature and a new moment-fitting quadrature rule are used. The hybrid quadrature schemes are systematically studied on flat B-spline patches and on NURBS spheres considering two different sphere discretizations: An exact single-patch sphere with degenerate control points at the poles and an approximate discretization that consist of six patches with regular elements. The efficiency of the quadrature schemes is further demonstrated in boundary element analysis for Stokes flow, where steady problems with rotating and translating curved objects are investigated in convergence studies for both, mesh and quadrature refinement. Much higher convergence rates are observed for the proposed new schemes in comparison to classical schemes.

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Authors (2)

Maximilian Harmel
Roger Sauer dr inż.

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Articles

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artykuły w czasopismach

Published in:

ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS no. 153, pages 172 - 200,
ISSN: 0955-7997

Language:

English

Publication year:

2023

Bibliographic description:

Harmel M., Sauer R.: New hybrid quadrature schemes for weakly singular kernels applied to isogeometric boundary elements for 3D Stokes flow// ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS -, (2023), s.172-200

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