Erratum for “Drag Coefficients in Nonsteady Turbulent Flow”
نویسندگان
چکیده
منابع مشابه
Drag reduction in the turbulent Kolmogorov flow.
We investigate the phenomenon of drag reduction in a viscoelastic fluid model of dilute polymer solutions. By means of direct numerical simulations of the three-dimensional turbulent Kolmogorov flow we show that drag reduction takes place above a critical Reynolds number Re(c). An explicit expression for the dependence of Re(c) on polymer elasticity and diffusivity is derived. The values of the...
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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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Two simple feedback control laws for drag reduction are derived by applying a suboptimal control theory to a turbulent channel flow. These new feedback control laws require pressure or shear-stress information only at the wall, and when applied to a turbulent channel flow at Reτ = 110, they result in 16–22% reduction in the skin-friction drag. More practical control laws requiring only the loca...
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In recent years extensive work has been focused onto using superhydrophobic surfaces for drag reduction applications. Superhydrophobic surfaces retain a gas layer, called a plastron, when submerged underwater in the Cassie-Baxter state with water in contact with the tops of surface roughness features. In this state the plastron allows slip to occur across the surface which results in a drag red...
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ژورنال
عنوان ژورنال: Journal of the Hydraulics Division
سال: 1972
ISSN: 0044-796X,2690-2524
DOI: 10.1061/jyceaj.0003321