Angular momentum transport in turbulent flow between independently rotating cylinders

Area of Science:

• Fluid dynamics
• Turbulence research
• Hydrodynamics

Background:

• Taylor-Couette flow is a fundamental system for studying fluid dynamics between rotating cylinders.
• Understanding angular momentum transport is crucial for various astrophysical and geophysical phenomena.

Purpose of the Study:

• To measure angular momentum flux (torque) in Taylor-Couette flow across all parameter spaces at high Reynolds numbers.
• To investigate the relationship between torque and the Rossby number.
• To compare experimental results with existing theories and previous experiments.

Main Methods:

• Experiments conducted using water in a Taylor-Couette apparatus with independently rotating inner and outer cylinders.
• Measurements performed across a wide range of angular velocities (Ω1, Ω2) at high Reynolds numbers.
• Analysis focused on the torque (G) and its dependence on the Rossby number (Ro).

Main Results:

• The Rossby number (Ro) was found to fully determine the flow state and torque (G).
• The ratio of torque to the torque at infinite Rossby number (G/G∞) exhibits a linear dependence on Ro(-1) in four distinct parameter space regions.
• Measured torques for flows with radially increasing angular momentum significantly exceed previous experimental findings.

Conclusions:

• The Rossby number is a key parameter governing torque in Taylor-Couette flow.
• The observed linear relationship provides a new understanding of angular momentum transport.
• Results support theoretical predictions and highlight discrepancies with prior experimental data.