Results 171 to 180 of about 1,669 (212)
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Drag Reduction in Pipes Lined with Riblets
AIAA Journal, 1990In the present paper, experiments are reported establishing a maximum drag reduction of five to seven percent in fully developed turbulent flow of water through 25.4mm and 50.8mm diameter pipes lined with a film of grooved equilateral triangles of base 0.11mm. The maximum reduction occurs when the height of the riblets is 11 to 16 wall units.
K. N. Liu +3 more
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Grinding of Riblets on Curved Paths
Materials Science Forum, 2016The grinding of riblets with multiple profiled grinding wheels is an efficient method to minimize the fluid friction on surfaces. In turbo machinery components, like pump impellers or compressor blades, the riblets must be ground with a curved tool path since the flow is rarely linear on such surfaces.
Berend Denkena, Thilo Grove, Jan Harmes
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1989
Riblets are little groves dug on the surface of flying or swimming solid bodies in order to reduce their drag. Why riblets work is not known but it is believed that it is a turbulent process because they trap the main eddies that develop near the solid body surfaces.
O. Pironneau, G. Arumugam
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Riblets are little groves dug on the surface of flying or swimming solid bodies in order to reduce their drag. Why riblets work is not known but it is believed that it is a turbulent process because they trap the main eddies that develop near the solid body surfaces.
O. Pironneau, G. Arumugam
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Secondary flow induced by riblets
Journal of Fluid Mechanics, 1998The effects of riblets on one wall of a channel bounding fully developed turbulent flow are investigated. Various perturbation elements including wires, fins and slots are modelled in order to understand the effects of riblets. It is found that widely spaced riblets, fins and wires create a substantial increase in turbulent activity just above ...
Goldstein, D. B., Tuan, T.-C.
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Riblet drag at flight conditions
Journal of Aircraft, 1989This paper describes perforated and nonperforated riblet tests on the fuselage of a modified Learjet model 28/29 twin-engine business jet at Reynolds numbers of 1.0-2.75 x 10/ft and Mach numbers of 0.3-0.7. Drag reductions of the order of 6% at nondimensional wall spacings of 12 were obtained using boundary-layer rakes and direct drag balances.
Michael J. Walsh +2 more
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Drag Reduction With Superhydrophobic Riblets
Volume 8: Mechanics of Solids, Structures and Fluids, 2012Samples combining riblets and superhydrophobic surfaces are fabricated at University of Pittsburgh and their drag reduction properties are studied at the Center for Nanophase Materials Sciences (CNMS) in Oak Ridge National Laboratory with a commercial cone-and-plate rheometer. In parallel to the experiments, numerical simulations are performed in order
Charlotte Barbier +2 more
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On Riblet's Theorem (Correspondence)
IEEE Transactions on Microwave Theory and Techniques, 1958Riblet presented the following theorem which is concerned with the synthesis of a quarter-wave impedance transformer.
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Yaw Angle Effects on Optimized Riblets
2001The drag reducing effect of riblets, has been demonstrated previously both experimentally and theoretically. Several aspects of the application of riblet film on an long range aircraft are considered. The aim of the present investigation is to check experimentally the effects of an angle of yaw on the performance of riblets.
Hage, W., Bechert, D. W., Bruse, M.
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Development of the wake of an airfoil with riblets
AIAA Journal, 1992Tests were conducted on a NACA 0012 airfoil with riblets at a freestream Reynolds number of 2.5 x 105 in an indraft wind tunnel. The riblets used in the investigation were of symmetric v-groove type with the heights of 0.0229, 0.076, and 0.152 mm.
J. M. Caram, A. Ahmed
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Smart Flow Control with Riblets
Advanced Materials Research, 2013A review of riblets as a smart flow control device is given. After the state-of-the-art examination of the drag reduction performance, different views on the drag reduction mechanism are put in perspective. Being a smart flow control device, riblets can control not only momentum, but also heat and flow noise.
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