Experimental investigation of torque hysteresis behaviour of Taylor–Couette Flow

M Gul,G E Elsinga,J Westerweel

doi:10.1017/jfm.2017.809

Abstract

This paper describes the hysteresis in the torque for Taylor–Couette flow in the turbulent flow regime for different shear Reynolds numbers, aspect ratios and boundary conditions. The hysteresis increases with decreasing shear Reynolds number and becomes more pronounced as the aspect ratio is increased from 22 to 88. Measurements conducted in two different Taylor–Couette set-ups depict the effect of the flow conditions at the ends of the cylinders on the flow hysteresis by showing reversed hysteresis behaviour. In addition, the flow structure in the different branches of the hysteresis loop was investigated by means of stereoscopic particle image velocimetry. The results show that the dominant flow structures differ in shape and magnitude depending on the branch of the hysteresis loop. Hence, it can be concluded that the geometry could have an effect on the hysteresis behaviour of turbulent Taylor–Couette flow, but its occurrence is related to a genuine change in the flow dynamics.

Highlights

Taylor–Couette flow occurs between two concentric and independently rotating cylinders
We performed torque and particle image velocimetry (PIV) measurements for different geometrical configurations and flow conditions to study the hysteresis in Taylor–Couette flow up to a shear Reynolds number of 5.5 × 104, which is beyond the transition regime, and can be considered as fully turbulent
The results for the torque show that the magnitude of the hysteresis decreases at higher shear Reynolds numbers, whereas it is increasing with increasing aspect ratio

Summary

Introduction

Taylor–Couette flow occurs between two concentric and independently rotating cylinders. Lathrop, Fineberg & Swinney (1992) proposed that a boundary layer transition to a turbulent regime occurs at a Reynolds number of 1.3 × 104 based on their highly accurate torque and wall shear stress measurements. Later, this finding was verified by local measurements by Lewis & Swinney (1999). We performed torque and particle image velocimetry (PIV) measurements for different geometrical configurations and flow conditions to study the hysteresis in Taylor–Couette flow up to a shear Reynolds number of 5.5 × 104, which is beyond the transition regime, and can be considered as fully turbulent.

Experimental set-up and methodology

Results

PIV measurements

Conclusions