The subgrid scale pressure field of scale-enriched Large Eddy Simulations using Gabor modes

TL;DR

This paper introduces a Gabor mode-based scale enrichment method for LES that accurately predicts small-scale pressure fields in turbulence without full non-linear simulations, improving computational efficiency.

Contribution

The paper presents a novel Gabor mode-based scale enrichment technique that effectively models small-scale turbulence effects in LES, especially for high Reynolds number flows.

Findings

Accurately extrapolates pressure spectrum.

Recovers pressure variance comparable to high-resolution LES.

Works well in both extit{a priori} and extit{a posteriori} analyses.

Abstract

With the continuing progress in large eddy simulations (LES), and ever increasing computational resources, it is currently possible to numerically solve the time-dependent and anisotropic large scales of turbulence in a large variety of flows. For some applications this large-scale resolution is satisfactory. However, a wide range of engineering problems involve flows at very large Reynolds numbers where the subgrid scale dynamics of a practical LES are critically important to design and yet are out of reach given the computational demands of solving the Navier Stokes equations; this difficulty is particularly relevant in wall-bounded turbulence where even the large-scales are often below the implied filter width of modest cost wall modeled LES (WMLES). In this paper we briefly introduce a scale enrichment procedure which leverages spatially and spectrally-localized Gabor modes. The method provides a physically consistent description of the small scale velocity field without solving the full non-linear equations. The enrichment procedure is appraised against its ability to predict small scale contributions to the pressure field. We find that the method accurately extrapolates the pressure spectrum and recovers pressure variance of the full field remarkably well when compared to a computationally expensive, highly resolved LES. The analysis is conducted both in \textit{a priori} and \textit{a posteriori} settings for the case of homogeneous isotropic turbulence (HIT).