Turbulent drag reduction by passive mechanisms
Article Abstract:
Experiments were undertaken in a fully developed turbulent channel flow wind-tunnel to demonstrate a passive means of controlling turbulence effectively. Specified protrusion patterns were introduced on the confining walls, interacting with energy bearing eddy structures, influencing the rate of energy dissipation. Small changes in protrusion arrangement were noted to alter the response of the system from drag decrease to drag enhancement.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1997
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The right sort of roughness: skin-friction drag affects any surface moving through a fluid
Article Abstract:
Skin friction drag is greater when a flow is turbulent as in many engineering applications, and new drag reduction methods have helped to advance the theories of turbulence. Sirovich and Karlsson have developed a drag reduction method, by artificially randomizing the phases of vortices and oblique waves in a channel flow, which led to less bursting and consequently, drag reduction.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1997
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Universality of turbulence
Article Abstract:
Bramwell and colleagues have reported the discovery of a new type of turbulence universality, linking it with the thermodynamic equilibrium of solids. They have demonstrated the rate of power consumption P(t) in turbulent flow enclosed in a air gap between two counter-rotating disks. They argue that the integral Re is at a fixed constant value and that flow is confined.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1998
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