Accession Number : ADD015067

Title :   Method and Apparatus for Reducing Drag and Noise Associated with Fluid Flow in a Conduit.

Descriptive Note : Patent Application, Filed 12 Jul 91,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Ng, Kam W

Report Date : 12 Jul 1991

Pagination or Media Count : 14

Abstract : A method and apparatus for reducing drag and noise associated with fluid flow within a conduit is provided. The conduit has flexible walls that are shaped to form stationary waves having peaks and troughs and are repeated in the axial direction of the conduit. The stationary waves are moved along the axial direction of the conduit whereby a vortex is trapped in the fluid flow at each of the troughs. Each of the vortices forms part of an isolating layer between the conduit wall and the main stream of the fluid flow thereby reducing drag. Furthermore, the vortices push the dominant noise producing region toward the center of the fluid flow where sound coupling efficiency is lower.

Descriptors :   CONDUITS, COUPLING(INTERACTION), DRAG, EFFICIENCY, FLEXIBLE STRUCTURES, FLUID FLOW, SOUND, STATIONARY, STREAMS, VORTICES, WALLS, WAVES

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE