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DNS/LES of Transitional Flow in Rotating Cavity
Ewa Tuliska-Sznitko and Artur Zielinski

In the present paper the 3D DNS and LES are performed to study the isothermal and non-isothermal transitional flow between two co- and counter-rotating disks enclosed by two rotating cylinders. Computations have been performed for the cavity of aspect ratio L=9 and curvature parameter Rm=1.5 and 3.0, for the wide range of the Reynolds numbers and for different end-wall conditions including throughflow. Attention is focused on instability structures, which appear in the different stages of laminar-turbulent transition, and on the stabilizing influence of cooling. Computations based on an efficient pseudo-spectral Chebyshev-Fourier method, brings new insight on the spatio-temporal characteristics of the isothermal and non-isothermal flows in rotating annular cavity. Three different patterns have been found: axisymmetric propagating vortices interpreted as type II instability, positive spiral vortices interpreted as type I instability and negative spirals. Obtained instability structures are compared with the results of experimental investigations of Schouveiler et al. (2001) and Gauthier et al. (2002). For the non-isothermal cases the distributions of Nusselt number in terms of disk radius were analyzed and compared with theoretical solutions.

Keywords: Laminar-turbulent transition, flow instability, rotating cavity, spectral methods, DNS, LES.

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