Mean Flow Evolution of Saturated Forced Shear Flows in Polytropic Atmospheres

TL;DR

This paper investigates the evolution of mean flow in saturated forced shear flows within polytropic atmospheres, highlighting complex behaviors beyond simple saturation mechanisms through numerical simulations.

Contribution

It introduces an analysis of mean flow evolution in shear-driven turbulence using the average relaxation method in polytropic atmospheres, revealing complex saturation behaviors.

Findings

Some systems saturate by restoring linear marginal stability

Results are more complex than initially expected

The average relaxation method provides insights into shear flow dynamics

Abstract

In stellar interiors shear flows play an important role in many physical processes. So far helioseismology provides only large-scale measurements, and so the small-scale dynamics remains insufficiently understood. To draw a connection between observations and three-dimensional DNS of shear driven turbulence, we investigate horizontally averaged profiles of the numerically obtained mean state. We focus here on just one of the possible methods that can maintain a shear flow, namely the average relaxation method. We show that although some systems saturate by restoring linear marginal stability this is not a general trend. Finally, we discuss the reason that the results are more complex than expected.