报告题目：Heat Transport in Turbulent Thermal Convection
报告人：Quan Zhou（Shanghai University）
Professor Quan ZHOU received his bachelor degree from University of Science and Technology of China in 2003. He obtained his PhD degree from the Chinese University of Hong Kong in 2008. Afterward, he was appointed as an Associate Professor at Shanghai Institute of Applied Mathematics and Mechanics in Shanghai University. He was promoted to a full Professor in 2012. In 2013, he received National Program for Support of Top-notch Young Professionals. He has published more than 30 journal papers including J. Fluid Mech., Phys. Rev. Lett., Phys. Fluids. His research interests include turbulence, heat and mass transfer, and experimental fluid mechanics. He is a member of the Editorial Board for ‘Scientific Reports’ and for ‘Journal of Hydrodynamics’.
Thermal convection is an efficient means to carry heat flux across space by a moving fluid, and it is ubiquitous in nature. A classical model system to study such phenomenon is Rayleigh-Bénard convection (RBC), i.e. the motion of a fluid layer that is heated from below and cooled from above. Due to the buoyancy instability the fluid moves and carries a heat flux upwards, which is typically many times of that by thermal diffusion. An important question to ask is how much heat flux moves through the RBC cell given an enclosed fluid and an imposed temperature difference across the cell.This heat flux is usually characterized by a non-dimensional parameter, defined as the Nusselt number Nu, which depends largely on the control parameters of the system, such as the Rayleigh number Ra, the Prandtl number Pr, and the aspect ratio of the convection cell. In this talk, I will introduce our recent works on heat transfer problems, i.e. the dependence of Nu on (Ra, Pr). Especially, I will report an experimental and numerical study that reveals a novel mechanism that leads to dramatically enhanced heat transport, i.e. when partition walls are inserted into a convection cell with thin gaps left open between the partition walls and the cooling/heating plates, it is found that the convective flow becomes much more coherent and self-organized, leading to a dramatically enhanced heat transport of up to 2.3 times that without any partitions. We expect that this surprising discovery might bring profound changes in many industrial applications where thermal flux through a fluid is involved.