A fourth-order finite difference scheme with accurate dispersion and adaptive dissipation for computational aeroacoustics

TL;DR

This paper introduces a new fourth-order finite difference scheme with adaptive dissipation and improved dispersion control for high-fidelity computational aeroacoustics, enhancing wave accuracy and reducing non-physical oscillations.

Contribution

It develops a novel dispersion control method using a modified scale sensor, leading to a scheme with accurate dispersion and adaptive dissipation for better acoustic simulations.

Findings

Achieves accurate dispersion for wavenumber k < 2.5

Dissipation is negligible at low wave numbers and increases to suppress oscillations

Outperforms conventional spectral optimized schemes in benchmark tests

Abstract

For computational acoustics, schemes need to have low-dispersion and low-dissipation properties in order to capture the amplitude and phase of the wave correctly. To improve the spectral properties of the scheme, the authors have previously proposed a scale sensor to automatically adjust the numerical dissipation. In consequence, a fourth-order finite difference scheme with minimized dispersion and adaptive dissipation (MDAD) has been proposed [1]. In this study, we further investigate this method for the high-fidelity numerical simulation of the acoustic problems and a new dispersion control method is proposed which is different from the traditional dispersion relation preserving (DRP) approach. Firstly, the scale sensor, which quantifies the local length scale of the solution as the effective scaled wavenumber, is modified for better performance on composite waves. Then the scale sensor is applied to control both the dispersion and dissipation of the scheme. The relationships between the dispersion/dissipation parameter and the effective scaled wavenumber are analytically and artificially constructed respectively. Thus, a fourth-order finite difference scheme with accurate dispersion and adaptive dissipation (ADAD) is constructed. The approximate dispersion relation (ADR) shows that the ADAD scheme achieves accurate dispersion property at k < 2.5. The dissipation is negligible at low wave number and gradually increases after k = 1 to suppress non-physical oscillations. Several benchmark cases of computational acoustics are presented to verify the high resolution of the proposed scheme compared with the conventional spectral optimized schemes.