Turbulent Taylor rolls: a localized self-sustained process

In many shear- and pressure-driven wall-bounded turbulent flows secondary motions spontaneously develop and their interaction with the main flow alters the overall large-scale features and transfer properties. The Taylor-Couette flow, the fluid motion developing in the gap between two concentric cylinders rotating at different angular velocity, is not an exception, and toroidal Taylor rolls have been observed from the early development of the flow up to the fully turbulent regime. In this talk we show that under the generic name of "Taylor rolls" there is a wide variety of structures that differ for the vorticity distribution within the cores, the way they are driven and their effects on the mean flow.

Other features of their dynamics are used to explain some transfer properties of the Taylor-Couette flow.