Heat transfer characterization of extreme rotating convection regimes in TROCONVEX

Many geophysical and astrophysical flows are driven by buoyant instabilities and heavily influenced by rotation. In lieu of the complexity of such systems, rotating Rayleigh-Bénard convection (RRBC) provides a simplified, canonical framework for understanding these flows. To date, however, laboratory experiments and numerical simulations cannot fully access the most geophysically-relevant regimes of rotating convection, which only emerge at extreme values of the governing parameters. Here we present a suite of heat transfer results from TROCONVEX, a new 4-meter-high rotating convection device capable of reaching Ekman numbers as low as 5x10^-9 and Rayleigh numbers as high as 10¹⁴ – both nearly an order of magnitude more extreme than previously achievable. We show that vertical temperature profiles are consistent with asymptotically-reduced RRBC results, and clearly reflect flow regime transitions. In addition, thermal measurements hint at the existence of novel flow structures in regimes beyond the scope of asymptotic simulations.