A unified view of energetic efficiency in active drag reduction, thrust generation and self-propulsion through a loss coefficient with application to flow past a circular cylinder with tangential surface motion

Arakeri, JH and Shukla, RK (2011) A unified view of energetic efficiency in active drag reduction, thrust generation and self-propulsion through a loss coefficient with application to flow past a circular cylinder with tangential surface motion. In: UNSPECIFIED, pp. 317-322.

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Abstract

An analysis of the energy budget for the general case of a body translating in a stationary fluid under the action of an external force is used to define a power loss coefficient. This universal definition of power loss coefficient gives a measure of the energy lost in the wake of the translating body and, in general, is applicable to a variety of flow configurations including active drag reduction, self-propulsion and thrust generation. The utility of the power loss coefficient is demonstrated on a model bluff body flow problem concerning a two-dimensional circular cylinder in a uniform cross flow. The upper and lower boundaries of the cylinder undergo continuous motion due to a prescribed reflectionally symmetric constant tangential surface velocity. It is shown that a gradual increase in the strength of the tangential surface velocity leads to a monotonic reduction in drag and eventual thrust production. With increasing magnitude of the tangential surface velocity the power loss coefficient first decreases and then increases after attaining a minima. At a Reynolds number of 100, minimum value of the power loss coefficient is obtained when the belt velocity is about three quarters of the free stream uniform velocity corresponding to a percentage drag reduction of approximately 54. © IUTAM Symposium on Bluff Body Flows, Blubof 2011.

Item Type:	Conference Paper
Publication:	IUTAM Symposium on Bluff Body Flows, Blubof 2011
Publisher:	Indian Institute of Technology, IIT, Kanpur
Additional Information:	The copyright for this article belongs to Indian Institute of Technology, IIT, Kanpur.
Keywords:	Budget control; Drag reduction; Reynolds number, Active drag; Energetic efficiency; Energy budgets; Loss coefficients; Powerloss; Self-propulsion; Stationary fluids; Surface motions; Surface velocity; Thrust generation, Circular cylinders
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	17 May 2024 08:55
Last Modified:	17 May 2024 08:55
URI:	https://eprints.iisc.ac.in/id/eprint/84583

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