二次元レイリー・ベナール対流における大規模循環の反転(対流(2),一般講演)

概要

論文の詳細を見る
The wind reversals of the large scale circulation in the two-dimensional Rayleigh-Benard convection are numerically studied with Rayleigh numbers up to Ra=10^9 and an aspect ratio of 1. For medium Prandtl numbers (e.g. those for air and water at ordinary temperature), there are a diagonal large scale convection roll and two smaller secondary rolls in the two remaining corners diagonally opposing each other. The corner flow rolls play a crucial role for the wind reversal: they grow in kinetic energy and thus also in size thanks to plume detachments from the boundary layers up to the time that they take over the main large scale diagonal flow, thus leading to reversal. The averaged time intervals between the reversals for various Rayleigh numbers are in good agreement with the experimentally measured ones. The probability density of the time interval reveals the preferred time scale. We map out the Rayleigh number versus Prandtl number phase space and find that the occurrence of reversals very sensitively depends on these parameters.
日本流体力学会の論文
2010-09-09