Accession Number : ADA298903

Title :   Unsteady Flow Distortion Past Blades: Source of Noise Generation in Rotating Flows.

Descriptive Note : Final rept.,

Corporate Author : LEHIGH UNIV BETHLEHEM PA DEPT OF MECHANICAL ENGINEERING AND MECHANICS

Personal Author(s) : Rockwell, Donald O.

PDF Url : ADA298903

Report Date : 02 JUL 1993

Pagination or Media Count : 9

Abstract : The overall goals of this program are to: (1) Determine the instantaneous flow structure past blading and interpret it in terms of pressure sources using high-image-density particle image velocimetry. In turn, these pressure source terms are to be decomposed into vorticity-related and rate-of-strain related contributions; (2) Establish active (open loop) control concepts for flow past blading. Generic leading-and trailing-edge interactions will be addressed. Control concepts are to incorporate harmonic, amplitude- and frequency-modulated disturbances. Attempts will be made to: (a) Destabilize normally coherent fluctuations into multiple-spectral or broadband distributions; (b) Restabilize modulated fluctuations to a periodic state; and (c) Modify the level of broadband fluctuations; (3) Implement active control concepts in a unique, actively-controlled radial flow machine, allowing arbitrary inflow and impeller perturbations. The flow structure in the machine is to be subjected to various phase-shifting concepts in order to optimize the flow control; and (4) Develop new approaches to high-density particle image velocimetry, involving innovative approaches to acquisition of images, as well as processing and post- processing of images to provide global, instantaneous insight. (KAR) p. 2

Descriptors :   *UNSTEADY FLOW, *DISTORTION, SOURCES, ACQUISITION, INTERACTIONS, FREQUENCY MODULATION, COHERENCE, BLADES, VARIATIONS, PARTICLES, IMAGES, BROADBAND, HIGH DENSITY, PRESSURE, PERTURBATIONS, CONTROL THEORY, VELOCIMETERS, MODULATION, ROTATION, OPEN LOOP SYSTEMS, PHASE SHIFT, TRAILING EDGES, NOISE GENERATORS, IMPELLERS.

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE