Study of convection in rotating flow in a new configuration with bi-directional temperature gradients*

Laboratory experiments were conducted in a novel configuration, comprising of non-homogeneously heated rotating cylindrical annulus, to study dynamics of rotating convection. Temperature time series measurements and flow visualization were done over a range of Taylor number, Ta (spanning 6.5 X 10⁸ - 2.7 X 10⁹)  and Rayleigh number, Ra (spanning 2.2 X 10⁸- 6.2 X 10⁸). Localized temperature time series data acquired by thermocouples, two point correlations of temperature data, Nusselt number characteristics, PIV imaging combined with 2D axisymmetric ANSYS Fluent simulation were used to understand the physics of baroclinic instabilities, convective structures and their interaction. Overall, it is speculated that heat transport in this new configuration is governed by the co-existence and interplay of convective plumes (above the heating zone that aid in the vertical transport of heat) and baroclinic waves/eddies (which aid in the horizontal transport of cold and hot fluids between the annuli). The two point temperature correlations show that these waves break into eddies as the value of Ta increases, which closely simulates the dynamics of geophysical motions. Scaling for the proposed system is derived and validated with thermal measurements.