Experimental and numerical study of the flow produced in a vertical Taylor-Couette system submitted to a large radial temperature gradient

The Taylor-Couette system has long been studied as a model for the study of the transition to turbulence in closed flows. In realistic situations, it is often necessary to take into account the presence of thermal effects. Here we describe and compare the results of experimental and numerical studies of the water flow produced in a Taylor-Couette system submitted to a large radial temperature gradient. Our system is composed of two vertical coaxial cylinders maintained at different temperatures. The inner cylinder is rotated whereas the outer one is at rest. The flow can be described by Ta, Gr and Pr: the Taylor, Grashof and Prandtl numbers. As soon as a radial temperature gradient is imposed between the cylinders, the flow takes the form of a vertical convective cell. When the inner cylinder starts to rotate, the circular Couette flow is added. Then, when the rotation of the inner cylinder is further increased and the Taylor number reaches a critical value which depends on Gr, this base flow is destabilized and leads to different states. For |Gr|>800, the pattern has a low frequency time modulation. For |Gr|>2500 , as soon as the Taylor number is slightly increased above its critical value, a pattern called solitary wave appears on the background of the modulated spiral.