The effects of large scales on the inertial range in high-Reynolds-number turbulence

TL;DR

This paper investigates how removing large-scale influences affects the inertial range in high-Reynolds-number turbulence, revealing significant impacts on structure functions and skewness, with implications for turbulence cascade theories.

Contribution

It provides new insights into the effects of large-scale removal on inertial range properties and the turbulence cascade process in high-Reynolds-number flows.

Findings

Structure functions are strongly affected across the inertial range.

Odd-order moments, especially skewness, are significantly reduced.

The interaction between small-scale energy and large-scale strain explains skewness reduction.

Abstract

The effects of removing large scales external to the inertial range on the properties of scales within the inertial range are studied in a high-Reynolds-number turbulent flow. Structure functions of both even and odd orders are strongly affected across the entire inertial range, but odd-order moments are affected to a greater degree. In particular, the skewness of velocity increments shows a significant reduction whereas the flatness changes comparatively little. The reduction in skewness is counterbalanced essentially by the interaction between the small-scale energy and the large-scale rate of strain. The implications of these results for the conventional cascade picture are examined briefly.