منابع مشابه
Drag reduction on a patterned superhydrophobic surface.
We present an experimental study of a low-Reynolds number shear flow between two surfaces, one of which has a regular grooved texture augmented with a superhydrophobic coating. The combination reduces the effective fluid-surface contact area, thereby appreciably decreasing the drag on the surface and effectively changing the macroscopic boundary condition on the surface from no slip to limited ...
متن کاملPolymer Drag Reduction and Bioluminescence Reduction
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...
متن کاملPolymer 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...
متن کاملDrag reduction and solvation in polymer solutions
A model is described which explains drag reduction (DR) in dilute polymer solutions in terms of solvation of macromolecular chains and formation of relatively stable domains. The domains partly suppress the vortex formation, act as energy sinks, and also play a role in mechanical degradation in flow (MDF). We report ultrasonically determined solvation numbers for a series of copolymers with the...
متن کاملViscous Drag Reduction with Surface-Embedded Grooves
Turbulent drag reduction in wall-bounded flows is investigated experimentally by considering the dynamic effects provoked by large variation of anisotropy in the velocity fluctuations. It is shown that high drag reduction is obtained when the velocity fluctuations near the wall reach the statistically axisymmetric state with invariance under rotation about the axis aligned with the mean flow. D...
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ژورنال
عنوان ژورنال: JSME International Journal Series C
سال: 1999
ISSN: 1344-7653,1347-538X
DOI: 10.1299/jsmec.42.634