Intermittency effects in rotating decaying turbulence

TL;DR

This study uses direct numerical simulations to analyze how rotation affects intermittency in decaying turbulence, revealing a reduction in intermittency perpendicular to the rotation axis, with implications for atmospheric and oceanic flows.

Contribution

It provides the first detailed numerical investigation of intermittency modulation in rotating turbulence, comparing results with recent experimental findings.

Findings

Intermittency decreases in the direction perpendicular to the rotation axis.

Numerical results align with recent experimental observations.

Rotation causes significant changes in turbulence structure and dispersion properties.

Abstract

Rotation modulates turbulence causing columnar structuring of a turbulent flow in case of sufficiently strong rotation. This yields significant changes in the flow characteristics and dispersion properties, which makes rotational turbulence modulation particularly relevant in the context of atmospheric and oceanic flows. Here we investigate the canonical flow of turbulence in a periodic box, subjected to rotation about a fixed vertical axis. As point of reference we consider direct numerical simulations of homogeneous isotropic turbulence. Modulation due to rotation at various rotation rates (i.e., different Rossby numbers) is investigated. Special attention is paid to the alteration of intermittency, which is measured in terms of changes in the scaling of the structure functions. A reduction of intermittency quantified with the longitudinal structure functions in the direction perpendicular to the rotation axes will be presented. These numerical findings correspond well to recent results obtained in experiments by Seiwert et al. (2008).