Aerodynamic Evaluation of Static and Dynamic Stability Characteristics of Double-Delta Wings

Vortex interactions and breakdown play a critical role in determining the static and dynamic stability of aircraft, particularly at high angles of attack. This study investigates the relationship between vortex interactions and aircraft stability characteristics, focusing on how chord ratio, angle of attack, and sideslip angle influence stability metrics. Utilizing force and moment measurements along with pressure-sensitive paint (PSP) for surface pressure distributions, the results show the effects of varying double-delta wing chord ratios at a target Mach number of 0.15. The stability metrics derived from force and moment measurements demonstrate directional stability improvements with increasing sideslip angle due to larger vortex-induced differential drag induced by advanced windward wing vortex breakdown. This asymmetric vortex breakdown was confirmed through PSP-measured surface pressure distributions. The study metrics revealed trend reversals in lateral stability due to the varying state of vortex systems on different models, and higher reduced frequencies, pitch rates, and chord ratios correlated with greater dynamic instability and sensitivity. This is attributed to the more rapid and extensive vortex breakdown associated with these higher parameters. These findings provide deeper insights into the flow physics governing high-alpha maneuvers, offering a foundation for future research, enhancing the design and performance of next-generation aircraft.