Turbulent drag in a rotating frame

Abstract

What is the turbulent drag force experienced by an object moving in a rotating fluid? This open and fundamental question can be addressed by measuring the torque needed to drive an impeller at constant angular velocity $\omega$ in a water tank mounted on a platform rotating at a rate $\Omega$. We report a dramatic reduction in drag as $\Omega$ increases, down to values as low as $12$\% of the non-rotating drag. At small Rossby number $Ro=\omega /\Omega$, the decrease in drag coefficient $K$ follows the approximate scaling law $K\sim Ro$, which is predicted in the framework of nonlinear inertial wave interactions and weak-turbulence theory. However, stereoscopic particle image velocimetry measurements indicate that this drag reduction rather originates from a weakening of the turbulence intensity in line with the two-dimensionalization of the large-scale flow.

To appear in Journal of Fluid Mechanics Rapids

References in corpus (4)

• Direct and inverse energy cascades in a forced rotating turbulence experiment
• Exact two-dimensionalization of rapidly rotating large-Reynolds-number flows
• Disentangling inertial waves from eddy turbulence in a forced rotating turbulence experiment
• Rotating Taylor-Green Flow

Cited by in corpus (13)

• Cascades and transitions in turbulent flows
• Quantitative experimental observation of weak inertial-wave turbulence
• Energy transfer in turbulence under rotation
• Condensates in rotating turbulent flows
• Shortcut to geostrophy in wave-driven rotating turbulence: the quartetic instability
• Critical transition in fast-rotating turbulence within highly elongated domains
• A magnetically driven equatorial jet in Europa's ocean
• Onset of three-dimensionality in rapidly rotating turbulent flows
• Two-dimensionalization of the flow driven by a slowly rotating impeller in a rapidly rotating fluid
• The onset of turbulent rotating dynamos at the low $Pm$ limit
• Dynamo saturation down to vanishing viscosity: strong-field and inertial scaling regimes
• Helicity dynamics, inverse and bi-directional cascades in fluid and MHD turbulence: A brief review
• An alternative view on dissipation in turbulent flows