Reorientation of daffodil(Narcissus : Amaryllidaceae) flowers inwind: drag reduction andtorsional flexibility
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چکیده
منابع مشابه
Polymer flexibility and turbulent drag reduction.
Polymer-induced drag reduction is the phenomenon by which the friction factor of a turbulent flow is reduced by the addition of small amounts of high-molecular-weight linear polymers, which conformation in solution at rest can vary between randomly coiled and rodlike. It is well known that drag reduction is positively correlated to viscous stresses, which are generated by extended polymers. Rod...
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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 interaction of the overlying turbulent flow with riblets, and its impact on their drag reduction properties are analysed. In the so-called viscous regime of vanishing riblet spacing, the drag reduction is proportional to the riblet size, but for larger riblets the proportionality breaks down, and the drag reduction eventually becomes an increase. It is found that the groove cross section A(...
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Bioluminescence represents an operational threat to U.S. Navy nighttime operations because of the vulnerability risk due to detection because of flow-stimulated light emission from naturally occurring plankton. Conversely, bioluminescence presents additional capabilities for detecting moving objects at night, particularly in the littoral zone where conventional acoustic surveillance is severely...
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Drag reduction by bubbles in stationary turbulent flows is sensitive to the compressibility of the bubbles. Without this dynamical effect the bubbles only renormalize the fluid density and viscosity, an effect that by itself can only lead to a small percentage of drag reduction. We show in this paper that the dynamics of bubbles and their effect on the compressibility of the mixture can lead to...
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ژورنال
عنوان ژورنال: American Journal of Botany
سال: 2000
ISSN: 0002-9122
DOI: 10.2307/2656682