The physics of stripe patterns in turbulent channel flow determined by DNS results

TL;DR

This paper uses DNS to analyze the formation and dynamics of stripe patterns in turbulent channel flow, revealing their characteristics and impact on flow parameters.

Contribution

It provides a detailed DNS-based analysis of stripe patterns in turbulent flow, including their motion, structure, and influence on global flow parameters.

Findings

Stripe patterns are observed and characterized in DNS simulations.

The relative motion of stripe patterns compared to mean flow is analyzed.

Global parameters like friction factor and Nusselt number are quantified.

Abstract

The turbulent flow in an infinitely extended plane channel is analysed by solving the Navier-Stokes equations with a DNS approach. Solutions are obtained in a numerical solution domain of finite size in the streamwise as well as in the lateral direction setting periodic boundary conditions in both directions. Their impact on large scale structures in the turbulent flow field is analysed carefully in order to avoid their suppression. When this is done appropriately well known stripe patterns in these flows can be observed and analysed especially with respect to their relative motion compared to the mean flow velocity. Various details of this stripe pattern dominated velocity field are shown. Also global parameters like the friction factor in the flow field and the Nusselt number in the temperature field are determined based on the statistics of the flow and temperature data in a very large time period that guarantees fully developed turbulent flow and heat transfer.