FINE SCALE EDDIES IN TURBULENT TAYLOR-COUETTE FLOW UP TO RE = 25 000

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Reynolds number effects on fine scale eddies in the turbulent Taylor-Couette flow have been investigated by high accuracy direct numerical simulations from Re = 8000 to 25 000. The Reynolds number dependency of the mean torque changes near Re = 10 000, and the transition is closely linked to the turbulence characteristics. As the Reynolds number increases, the fine scale eddies are more densely populated and take more various tilting angles. The joint probability density function of the tilting angle and the radial position exhibits a preferential pattern corresponding to the large scale motion of Taylor vortices. The present results suggest that in this Reynolds number range, the fine scale eddies progressively prevail a large part of the domain, and their contribution to the fundamental statistics such as the Reynolds shear stress becomes more evident.