Accession Number : ADA303750

Title :   Laser Doppler Velocimetry and Viscous Computation of the Flow Through a Compressor Cascade Near Stall.

Descriptive Note : Master's thesis,

Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s) : Williams, Andrew J.

PDF Url : ADA303750

Report Date : JUN 1995

Pagination or Media Count : 118

Abstract : Laser-Doppler velocimeter measurements were made in the flow field of a stalled cascade of controlled-diffusion stator blades. Tests were conducted at 10 degrees of incidence above the design inlet-flow angle in order to verify previous measurements. A unique method of data presentation was offered to characterize the unsteady positive and negative velocities about their mean. Laser-sheet flow visualization was performed and showed the unsteadiness of the stalling phenomena within the blade row passages. Additionally, a leading-edge separation bubble was observed and reversed flow was measured within the bubble using the laser-Doppler anemometer. Power-spectral density and auto-correlation analysis results are presented. In parallel with the experimental measurements, a computational fluid-dynamics study was initiated in an attempt ultimately to predict stall. Viscous flow computations were completed at on-design and near-stall conditions. Pressure distributions, separation bubble re-attachment locations, and loss predictions were compared to previous experimental studies. Generally good agreement was obtained for on-design conditions with degradation in prediction nearing stall. (AN)

Descriptors :   *FLOW VISUALIZATION, *VISCOUS FLOW, *LASER VELOCIMETERS, ALGORITHMS, AUTOCORRELATION, THESES, TURBULENCE, POWER SPECTRA, COMPUTATIONAL FLUID DYNAMICS, PRESSURE MEASUREMENT, FLOW FIELDS, STALLING, MATHEMATICAL PREDICTION, BUBBLES, WAKE, LEADING EDGES, MACH NUMBER, UNSTEADY FLOW, NAVIER STOKES EQUATIONS, FLOW SEPARATION, PRESSURE DISTRIBUTION, GAS SURFACE INTERACTIONS, SUBSONIC WIND TUNNELS, LASER ANEMOMETERS, CASCADES(FLUID DYNAMICS), AXIAL FLOW COMPRESSOR BLADES.

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE