Streamwise oscillation of spanwise velocity at the wall of a channel for turbulent drag reduction
نویسندگان
چکیده
منابع مشابه
Streamwise-traveling waves of spanwise wall velocity for turbulent drag reduction
Waves of spanwise velocity imposed at the walls of a plane turbulent channel flow are studied by Direct Numerical Simulations. We consider sinusoidal waves of spanwise velocity which vary in time and are modulated in space along the streamwise direction. The phase speed may be null, positive or negative, so that the waves may be either stationary or traveling forward or backward in the directio...
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متن کاملTurbulent Drag Reduction by Spanwise Wall Oscillations
The objective of this paper is to examine the effectiveness of wall oscillation as a control scheme of drag reduction. Two flow configurations are considered: constant flow rate and constant mean pressure gradient. The Navier-Stokes equations are solved using Fourier-Chebyshev spectral methods and the oscillation in sinusoidal form is enforced on the walls through boundary conditions for the sp...
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The drag reduction properties of a turbulent channel flow modified by spanwise sinusoidal oscillations of the walls are investigated by direct numerical simulations. The work is based on the linear relation between the drag reduction and the parameter S, function of the maximum wall velocity and the period of the oscillation. This quantity, first determined by JI-Choi et al. (2002) and later st...
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Measurements of the streamwise and spanwise fluctuating velocity components are obtained in a high Reynolds number turbulent boundary layer using custom made sub-miniature hot wires. These measurements are made over a range of Reynolds numbers from Reτ ≈ 3,000 to Reτ ≈ 10,500, but at fixed unit Reynolds number U∞/ν (Reτ = δUτ/ν; where ν is the kinematic viscosity, Uτ is the friction velocity an...
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ژورنال
عنوان ژورنال: Physics of Fluids
سال: 2009
ISSN: 1070-6631,1089-7666
DOI: 10.1063/1.3266945