Many problems in fluid dynamics are effectively modeled as Stokes flows — slow,
viscous flows where the Reynolds number is small. Boundary integral equations
are often used to solve these problems, where the fundamental solutions
for the fluid velocity are the Stokeslet and stresslet. One of the main challenges
in evaluating the boundary integrals is that the kernels become singular
on the surface. A regularization method that eliminates the singularities
and reduces the numerical error through correction terms for both the Stokeslet
and stresslet integrals was developed by Tlupova and Beale (J. Comput. Phys.386 (2019), 568–584). In this work we build on the previously developed
method to introduce a new stresslet regularization that is simpler and results
in higher accuracy when evaluated on the surface. Our regularization replaces
a seventh-degree polynomial that results from an equation with two conditions
and two unknowns with a fifth-degree polynomial that results from an equation
with one condition and one unknown. Numerical experiments demonstrate
that the new regularization retains the same order of convergence as the
regularization developed by Tlupova and Beale but shows a decreased magnitude
of the error.
Keywords
Stokes flow, boundary integral equations, regularization