Accession Number : ADP005903

Title :   Investigation on the Movement of Vortex Burst Position with Dynamically Changing Angle of Attack for a Schematic Deltawing in a Watertunnel with Correlation to Similar Studies in Windtunnel,

Corporate Author : SAAB-SCANIA A B LINKOEPING (SWEDEN)

Personal Author(s) : Wolffelt, Karl W.

Report Date : JUN 1987

Pagination or Media Count : 8

Abstract : Requirements for modern military aircraft to maintain good handling qualities at very high angles of attack is one of many reasons why as increased knowledge is necessary regarding the aerodynamic behaviour of vortex flows at non-stationary conditions. Linearized theory as it has been used in flight mechanics simulation using damping derivatives derived from for example forced oscillation technique, may no longer be valid at such conditions. With this background some investigations have been made by SAAB-SCANIA with the aim to study the hysteresis effects for non-stationary vortex flows. A schematic deltawing model which could also be equipped with a similar canardwing was tested in a watertunnel. The model was supported in the watertunnel by a simple mechanism by which it could be forced to move in one of four different modes - pitching or plunging with either ramp or harmonic motion. The flow over analyzed and the movements of the leading edge vortex burst have been studied with the main interest focused on the hysteresis effects.

Descriptors :   *VORTICES, FLOW FIELDS, LEADING EDGES, HYSTERESIS, ANGLE OF ATTACK, MODEL TESTS, WATER TUNNELS, FLOW VISUALIZATION, PITCH(MOTION), DELTA WINGS, EXPERIMENTAL DATA, CORRELATION, WIND TUNNEL TESTS, SWEDEN.

Subject Categories : Aerodynamics
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE