Physical Mechanism behind the Early Onset of the Ultimate State in Supergravitational Centrifugal Thermal Convection

Abstract

We present a combined experimental and numerical investigation of the transition from the classical to the ultimate regime of thermal turbulence in a supergravitational centrifugal convection system. The transition is found to be robust, with the critical Rayleigh number decreasing systematically as the Froude number, defined as the ratio of centrifugal to Earth's gravity, decreases, highlighting the effect of residual gravity. Once the Rayleigh number reaches the transition threshold, the Stewartson layer induced by residual Earth gravity becomes comparable in thickness to the viscous boundary layer, and their interaction results in a coupled flow that distorts the viscous boundary layer, triggering its transition from laminar to turbulent flow and leading to a sharp increase in heat transport. These findings demonstrate the key role of the Stewartson layer induced by residual gravity in facilitating the transition to the ultimate regime in supergravitational centrifugal thermal convection.

arXiv comment7 pages, 4 figures

References in corpus (10)

• Large scale dynamics in turbulent Rayleigh-Benard convection
• Prandtl-, Rayleigh-, and Rossby-number dependence of heat transport in turbulent rotating Rayleigh-Benard convection
• AFiD-GPU: a versatile Navier-Stokes Solver for Wall-Bounded Turbulent Flows on GPU Clusters
• The role of Stewartson and Ekman layers in turbulent rotating Rayleigh-Bénard convection
• Boundary Zonal Flow in Rotating Turbulent Rayleigh-Bénard Convection
• A Heuristic Framework for Next-Generation Models of Geostrophic Convective Turbulence
• Supergravitational turbulent thermal convection
• Evidences for the existence of the ultimate regime in supergravitational turbulent thermal convection
• Logarithmic temperature profiles in the ultimate regime of thermal convection
• Gravity drives the flow within the Stewartson layer in centrifugal convection