Title: An improved high order finite difference method for non-conforming grid interfaces for the wave equation,
Abstract: This paper presents an extension of a recently developed high order finite
difference method for the wave equation on a grid with non-conforming
interfaces. The stability proof of the existing methods relies on the
interpolation operators being norm-contracting, which is satisfied by the
second and fourth order operators, but not by the sixth order operator. We
construct new penalty terms to impose interface conditions such that the
stability proof does not require the norm-contracting condition. As a
consequence, the sixth order accurate scheme is also provably stable. Numerical
experiments demonstrate the improved stability and accuracy property.