Transition to inverse cascade in turbulent rotating convection in absence of the large-scale vortex

Abstract

Turbulent convection under strong rotation can develop an inverse cascade of kinetic energy from smaller to larger scales. In the absence of an effective dissipation mechanism at the large scales, this leads to the pile-up of kinetic energy at the largest available scale, yielding a system-wide large-scale vortex (LSV). Earlier works have shown that the transition into this state is abrupt and discontinuous. Here, we study the transition to the inverse cascade at Ekman number $\text{Ek}=10^{-4}$ and using stress-free boundary conditions, in the case where the inverse energy flux is dissipated before it reaches the system scale, suppressing the LSV formation. We demonstrate how this can be achieved in direct numerical simulations by using an adapted form of hypoviscosity on the horizontal manifold. We find that in the absence of the LSV, the transition to the inverse cascade becomes continuous. This shows that it is the interaction between the LSV and the background turbulence that is responsible for the earlier observed discontinuity. We furthermore show that the inverse cascade in absence of the LSV has a more local signature compared to the case with LSV.

References in corpus (10)

• Approaching the Asymptotic Regime of Rapidly Rotating Convection: Boundary Layers vs Interior Dynamics
• Inverse cascade and symmetry breaking in rapidly-rotating Boussinesq convection
• Large-scale vortices in rapidly rotating Rayleigh-Bénard convection
• The effects of Ekman pumping on quasi-geostrophic Rayleigh-Benard convection
• Subcritical turbulent condensate in rapidly rotating Rayleigh-Bénard convection
• On the edge of an inverse cascade
• Discontinuous Transitions Towards Vortex Condensates in Buoyancy-Driven Rotating Turbulence
• Bistability of the large-scale dynamics in quasi-two-dimensional turbulence
• The Effects of Rotation Rate on Deep Convection in Giant Planets with Small Solid Cores
• Transitions of turbulent superstructures in generalized Kolmogorov flow