Accession Number : ADA297517

Title :   Structure and Control of Three-Dimensional Unsteady Flow in Delta Wings at High Angle-of-Attack.

Descriptive Note : Final rept. 15 Nov 93-14 ov 94,

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

Personal Author(s) : Rockwell, Donald

PDF Url : ADA297517

Report Date : 22 MAR 1995

Pagination or Media Count : 8

Abstract : This program has focused on the instantaneous flow structure generated by controlled motion of wings in the pitching and rolling modes, as well as application of local control techniques for mediating the flow structure. The instantaneous flow structure is characterized using high-image-density particle image velocimetry, in conjunction with new types of two and three dimensional imaging techniques. This approach provides instantaneous velocity fields, streamline patterns and vorticity distributions at crucial locations in the flow field and allows a proper basis for eventual control of the flow structure. Characterization of the flow structure in the rolling mode of wing motion has involved definition of the critical states of the flow, based on the static locations of onset of vortex breakdown. The instantaneous crossflow and streamwise topology has been defined as a function of row angle. For pitching motion of the wing, simultaneous maneuver of the wing and application of control in the form of deflection of a leading-edge flap and blowing from the trailing-edge provide an effective, interactive means of altering the onset of vortex breakdown, thereby enhancing the effectiveness of maneuvers at high angle of attack.

Descriptors :   *ANGLE OF ATTACK, *UNSTEADY FLOW, *DELTA WINGS, *HIGH ANGLES, *THREE DIMENSIONAL FLOW, VELOCITY, ANGLES, POSITION(LOCATION), ROLL, PITCH(MOTION), FLIGHT CONTROL SYSTEMS, DEFLECTION, MOTION, VORTICES, FLOW FIELDS, TOPOLOGY, SYNCHRONISM, FLIGHT MANEUVERS, WINGS, STATICS, CROSS FLOW, LEADING EDGE FLAPS.

Subject Categories : Fluid Mechanics
      Flight Control and Instrumentation

Distribution Statement : APPROVED FOR PUBLIC RELEASE