Effect of gap width on turbulent transition in Taylor-Couette flow

TL;DR

This study uses simulations to analyze how increasing gap width in Taylor-Couette flow stabilizes the flow and delays turbulence, highlighting the importance of radius ratio effects.

Contribution

It reveals the stabilizing effect of larger gap widths on turbulent transition and emphasizes the role of the radius ratio in flow characterization.

Findings

Flow becomes more stable with increased gap width.

Average velocity approaches free vortex flow as gap widens.

Larger gap width delays turbulent transition by reducing energy gradient maxima.

Abstract

Simulations of the transitional flow in Taylor-Couette configuration are carried out to study the effect of the gap width on turbulent transition. The research results show that, under the same radius and the rotating speed of the inner cylinder, as the gap width increases, the flow becomes more stable. It is discovered that the average velocity distribution in the gap approaches the free vortex flow as the width increase and the stability of the flow is enhanced. It is found that, as the gap width increases, the maximum of the energy gradient function (from the energy gradient theory) in the gap decreases, which delays the turbulent transition. As such, the larger the gap width, the later the transition occurs. As the gap width increases, the Reynolds number based on the gap width alone is not able to characterize the flow behavior in Taylor-Couette flows, and the effect of the radius ratio should be taken into account.