# Effect of filter type on the statistics of energy transfer between resolved and subfilter scales from a-priori analysis of direct numerical simulations of isotropic turbulence

## TL;DR

This study investigates how different filtering methods affect the statistical properties of energy transfer between resolved and sub-filter scales in isotropic turbulence, using high-resolution DNS data and a priori analysis.

## Contribution

It introduces a comparison of various spectral filters, including a novel Galerkin projector, to assess their impact on SFS energy transfer statistics and intermittency scaling.

## Key findings

- Local SFS energy transfer shows intermittency scaling in skewness and flatness.
- Filtering type influences the robustness of scaling.
- Galilean invariance plays a significant role in the analysis.

## Abstract

The effects of different filtering strategies on the statistical properties of the resolved-to-sub-filter scale (SFS) energy transfer are analyzed in forced homogeneous and isotropic turbulence. We carry out a priori analyses of statistical characteristics of SFS energy transfer by filtering data obtained from direct numerical simulations (DNS) with up to $2048^3$ grid points as a function of the filter cutoff scale. In order to quantify the dependence of extreme events and anomalous scaling on the filter, we compare a sharp Fourier Galerkin projector, a Gaussian filter and a novel class of Galerkin projectors with non-sharp spectral filter profiles. Of interest is the importance of Galilean invariance and we confirm that local SFS energy transfer displays intermittency scaling in both skewness and flatness as a function of the cutoff scale. Furthermore, we quantify the robustness of scaling as a function of the filtering type.