Set-Up of Anisotropy in a Spanwise Rotating Channel
Development of anisotropy in a spanwise rotating channel is analyzed in time and space through direct numerical simulations. The aim is to understand how the anisotropy sets-up both in time and space in a supercritical flow, the role of rotation being rather generic in this particular context. Several techniques to quantify anisotropy are used such as the trajectories in time and space of the Lumley invariants, the dissipation tensor invariants and local anisotropy characterization in the spectral domain. It is shown that large excursions within the Lumley triangle occur near the centerline, and the local perturbation hesitates for long time between a one component to a nearly isotropic state. The wall damps these excursions; the local turbulence structure changes only slightly near the wall and it remains basically axisymmetric.
KeywordsDirect Numerical Simulation Spanwise Direction Local Perturbation Wall Turbulence Turbulent Spot
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