Instantaneous topology of the unsteady leading-edge vortex at high angle of attack
1993; American Institute of Aeronautics and Astronautics; Volume: 31; Issue: 8 Linguagem: Inglês
10.2514/3.11786
ISSN1533-385X
AutoresC. Magness, Owen Robinson, D. Rockwell,
Tópico(s)Fluid Dynamics and Vibration Analysis
ResumoA new topological structure is defined for flow over a delta wing undergoing transient pitching maneuvers at high angle of attack. This instantaneous structure differs substantially from the traditional topology observed for stationary wings at low angle of attack. The leading edge vortex is found to exhibit an outward-spiraling motion corresponding to an unstable focus. In addition, the streamlines separating from the leading edge are not entrained into the vortex core in the instantaneous sense. The instantaneous topology is determined from highresolution measurements over the crossflow plane by locating and categorizing the critical points of the instantaneous sectional streamlines. The three-dimensional, instantaneous streamline pattern corresponding to this topological structure is constructed by phase referencing the velocity fields at various chordwise locations. This approach allows three-dimensional characterization of the unstable focus of the leading-edge vortex and its relation to the feeding sheet.
Referência(s)