BAROCLINIC WAVES IN A SHALLOW ROTATING ANNULUS WITH TEMPERATURE-GRADIENTS IMPOSED ON THE HORIZONTAL BOUNDARIES

Abstract

A numerical investigation is made of flow and heat transfer characteristics of baroclinic waves using a new rotating cylindrical annulus, referred to as the Miller-Fowlis (MF) model: Special features of this annulus are: (1) the aspect ratio (height to width) is small, (2) the thermal gradients are imposed on the horizontal boundaries. In an effort to expand upon the previous experimental measurements, comprehensive numerical data ate acquired for the finite-amplitude wave-present flow regime. Full three-dimensional Navier-Stokes equations are solved by utilizing a well established pseudospectral numerical technique. Three specific case studies are performed by using the parameter values which are selected by consulting the experimentally-obtained regime diagrams. The three-dimensional computations successfully captured the existence of finite-amplitude waves. Salient features of three-dimensional flow and thermal fields are presented. Both the zonal mean and deviatoric fields of essential flow variables are displayed and pertinent physical interpretations are attempted. Comprehensive examinations of flow properties and energetics are undertaken; post processing analyses and discussions are rendered. In the present MF model, the sidewall layers are passive in nature; the dominant character of global flow is determined by the Ekman layers. The zonal mean flow field is characterized by a triple-cell structure which consists of two dominant cells and a weak central cell. The similarities and discrepancies between the results of the present model and of the conventional rotating annulus model are delineated.