On the Absence of the Ultimate Regime in Turbulent Thermal Convection

Abstract: Quantifying heat transport in turbulent convection remains a challenge. The two competing models of heat transport predict that heat transport scales as (ultimate regime scaling) or (classical scaling), where “” is the temperature difference between the top and bottom plates that confine the fluids. The speaker and his team’s synergetic and comparative study indicates the latter scaling. Using extreme numerical simulations, they demonstrate that the positive and negative energy fluxes in turbulent convection are nearly equal; however, the positive flux prevails over the negative flux, with the difference scaling as , which leads to a scaling. The above robust and universal properties are attributed to the confining thermal plates. The features differ significantly from those of periodic convection, which is often related to the ultimate regime. Towards the end of the talk, the speaker will briefly discuss the heat transport in moist turbulent convection. He aims to simulate moist convection at parameters of the Earth’s environment.

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Bio: Professor Mahendra Kumar Verma is a distinguished theoretical physicist at Indian Institute of Technology Kanpur, known for his contributions to turbulence, nonlinear dynamics, and statistical physics; he completed his Bachelor of Technology (undergraduate) in Computer Science from Indian Institute of Technology Madras and his Ph.D. in physics from the
University of Maryland. He is a recipient of the J. C. Bose Fellowship, Swarnajayanti Fellowship, Cray HPC Award, and INSA Teachers Award, and a fellow of the three Indian
science academies. He has authored several books, including Introduction to Mechanics, Energy Transfers in Fluid Flows, and Physics of Buoyant Flows.