Accession Number : ADA325168

Title :   LDA Measurements over an Oscillating Rectangular Wing.

Descriptive Note : Final rept. 1 May 95-31 Dec 96,

Corporate Author : WASHINGTON STATE UNIV PULLMAN

Personal Author(s) : Ramaprian, B. R.

PDF Url : ADA325168

Report Date : 14 MAR 1997

Pagination or Media Count : 38

Abstract : Experimental results of measurement of the phase-locked velocity distributions in the three-dimensional vortical region over the tip region of a rectangular wing oscillating sinusoidally about its quarter-chord axis are reported. The tests were conducted in a low-speed wind tunnel at a Reynolds number of 350,000 and velocity measurements were made using a three-component Laser Doppler Anemometer (LDA). The wing was oscillated at a frequency of 1 HZ and an amplitude of 4 degrees about a mean angle of incidence of 15 degrees. The data indicate that under the conditions tested, there is no massive flow reversal occurring anywhere over the tip region. The velocity distributions were however highly distorted from the usual boundary layer-like shapes and exhibited significant hysteresis between the pitch-up and pitch-down parts of the oscillating cycle. There was a small but significant amount of cross-flow even at the most inboard station measured. The vicinity of the wing tip was characterized by a strong axial vortex, which originated at a distance of about 30% chord from the leading edge and grew to a size of about 20% chord at the trailing edge. The extensive set of velocity data have been archived on electronic storage and are available to any interested user.

Descriptors :   *STALLING, *AERODYNAMICS, *THREE DIMENSIONAL FLOW, PITCH(MOTION), VORTICES, FLOW FIELDS, RECTANGULAR BODIES, WIND TUNNEL TESTS, UNSTEADY FLOW, PRESSURE DISTRIBUTION, REYNOLDS NUMBER, BOUNDARY LAYER FLOW, AXIAL FLOW, WING TIPS, CROSS FLOW, LASER ANEMOMETERS.

Subject Categories : Aerodynamics
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE