WENO reconstructions of unconditionally optimal high order
Antonio Baeza, Raimund Bürger, Pep Mulet, David Zorío
TL;DR
This work tackles the problem of accuracy loss in high-order WENO reconstructions near critical points of any order. It introduces OWENO, a reconstruction with non-dimensional, scale-independent weights that rely only on local stencil data, supported by theoretical bounds on smoothness indicators and a novel indicator-based construction. The key contributions include a new smoothness indicator $d_2$ and a harmonic-mean-type combination $D_r$ that ensure unconditionally optimal order $2r-1$ for $r\ge3$, plus extensive numerical validation on smooth and discontinuous problems in one and multi-dimensions. The approach yields robust, high-accuracy reconstructions for hyperbolic conservation laws with competitive computational cost, and it opens avenues for extending unconditional optimality to lower-order schemes and further parameter optimization.
Abstract
A modified Weighted Essentially Non-Oscillatory (WENO) reconstruction technique preventing accuracy loss near critical points (regardless of their order) of the underlying data is presented. This approach only uses local data from the reconstruction stencil and does not rely on any sort of scaling parameters. The key novel ingredient is a weight design based on a new smoothness indicator, which defines the first WENO reconstruction procedure that never loses accuracy on smooth data, regardless of the presence of critical points of any order, and is therefore addressed as optimal WENO (OWENO) method. The corresponding weights are non-dimensional and scale-independent. The weight designs are supported by theoretical results concerning the accuracy of the smoothness indicators. The method is validated by numerical tests related to algebraic equations, scalar conservation laws, and systems of conservation laws.
