Reconstruction of the 3D flow field in a differentially heated rotating annulus by synchronized particle image velocimetry and infrared thermography measurements

In the earth’s atmosphere baroclinic instability is responsible for the heat and momentum transport from low to high latitudes. Baroclinic instability leads to the growth of multi-scale vortices that accomplish the meridional heat transport. Raymond Hide used a rather simple laboratory experiment to study such vortices in the lab (Hide, 1953). The experiment is comprised by a cooled inner and heated outer cylinder mounted on a rotating platform, which mimics the heated tropical and cooled polar regions of the earth’s atmosphere. The working fluid is water, though recent experiments have also been carried out using air. The experiment shows rich dynamics that have been studied by varying the radial temperature difference and the rate of annulus revolution W. Keeping the temperature gradient fixed, an azimuthally symmetric flow regime can be found for small W. By increasing W, the flow transitions to a wavy regime that becomes chaotic for large W.