Meridional Flow Field of Axisymmetric Flows in a Rotating Annulus

Abstract

Measurements of the flow field were made of the axisymmetric flow in a differentially heated rotating fluid annulus by using a long-term tracking of a tracer particle. Its meridional flow profile is composed of a flow circulating in a large direct (Hadley) cell, which consists of thin boundary and top horizontal layers, and another one in the interior of that cell. Our measurements show that little mixing of the flow between the Hadley cell and the interior occurs and two secondary cells exist in the interior. These cells cause a trajectory of the tracer particle to be chaotic, where the particle follows the main cyclic route but is occasionally trapped in the secondary cells for indefinite times. Very close to the transition to the wave regime, a mixed structure appears consisting of both the axisymmetric and the wave flows in the meridional flow field: an unsteady wave flow occurs in the interior of the Hadley cell.