Motion Effects on Leading-Edge Vortex Behavior over Delta Wings and Generalized Modeling
Abstract
Effects of static attitude and three different motions on vortex behavior and its breakdown over delta wings were investigated. These motions include the following: (1) harmonic oscillation or ramp-and-hold motion in roll at constant resultant angle of attack, (2) harmonic oscillation or ramp-and-hold in pitch, and (3) coning at constant resultant angle of attack. A basic 65 degree delta wing configuration was tested in two wind tunnels as well as in a water tunnel. A roll rig, pitch rig, and coning rig (OPLEC) were employed for the investigation. Quite different flow characteristics were found within the spiral vortex breakdown region even under steady conditions. The point where vortex breaks down into large-scale turbulence has a very long response time to perturbations and is the major cause for the dramatic time dependence observed in the airloads. In addition, bi-stable vortex breakdown locations are observed in the case of slender delta wings when breakdown is located close to the trailing edge. Under dynamic conditions, the behavior of the vortex and its breakdown region were found to be highly dependent on motion waveform and reduced angular rates. An analytical model based on the Nonlinear Indicial Response Method and a formulation suggested by Tobak et al. and capable of reflecting the above effects is proposed to predict breakdown location under dynamic conditions. (24 figures, 12 refs.)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 2003
- Accession Number
- ADA419066
Entities
People
- E. S. Hanff
- X. Z. Huang
Organizations
- National Research Council Canada