Approximate deconvolution large eddy simulation of a stratified two-layer quasigeostrophic ocean model

TL;DR

This paper develops an approximate deconvolution large eddy simulation model for stratified ocean dynamics, demonstrating its effectiveness and sensitivity to different spatial filters in capturing key features with reduced computational cost.

Contribution

The paper introduces an AD-LES model for two-layer quasigeostrophic equations and compares two spatial filters, highlighting their impact on dissipation and model accuracy.

Findings

AD-LES with filters reproduces DNS results at lower cost

Tridiagonal filter introduces less numerical dissipation

Differential filter adds significant dissipation at larger widths

Abstract

We present an approximate deconvolution (AD) large eddy simulation (LES) model for the two-layer quasigeostrophic equations. We applied the AD-LES model to mid-latitude two-layer square oceanic basins, which are standard prototypes of more realistic stratified ocean dynamics models. Two spatial filters were investigated in the AD-LES model: a tridiagonal filter and an elliptic differential filter. A sensitivity analysis of the AD-LES results with respect to changes in modeling parameters was performed. The results demonstrate that the AD-LES model used in conjunction with the tridiagonal or differential filters provides additional dissipation to the system, allowing the use of a smaller eddy viscosity coefficient. Changing the spatial filter makes a significant difference in characterizing the effective dissipation in the model. It was found that the tridiagonal filter introduces the least amount of numerical dissipation into the AD-LES model. The differential filter, however, added a significant amount of numerical dissipation to the AD-LES model for large values of the filter width. All AD-LES models reproduced the DNS results at a fraction of the cost within a reasonable level of accuracy.