CRITICAL STATES AND FLOW STRUCTURE ON A 65-DEG DELTA-WING

Swept and delta wings maneuvering at moderate and high angles of attac k produce highly nonlinear and often discontinuous aerodynamic forces and moments that are difficult to model. The nonlinear indicial respon se (NIR) methodology and the concept of critical states accompanied by changes in the flow structure and topology could provide a rational f ramework for the analyses and modeling of these lows. The analysis of surface oh-how photographs and laser light sheet high-speed video imag es of smoke flow has been performed. The correlation of the structural and topological changes in the flow with force and moment data follow s. Critical states are often accompanied by changes in the how topolog y and not all topological changes produce measurable changes in the fo rces and moments, however, a useful relationship may exist.