Contributions to Commercial Supersonic Aircraft Technology: Low-Speed Aerodynamic Design and Active Aeroelastic Control

Abstract

This dissertation describes contributions to commercial supersonic technology in two areas: low-speed wind tunnel aerodynamic testing and analysis and active aeroelastic control with wind tunnel aeroservoelastic demonstrations and evaluation. The NASA Supersonic Configurations at Low Speeds (SCALOS) project addresses the research gap between the much needed work on low-speed characteristics that affect takeoff, approach, and landing of commercial supersonic aircraft and the high-speed cruise-optimized conditions on which existing designs and publications have focused for years. The SCALOS wind tunnel campaign spanned five years, with eight entries, 1415 runs, and 61.5 occupancy test days at the University of Washington’s Kirsten Wind Tunnel, producing a low-speed aerodynamic database of supersonic configurations and their parametric variations, together with the dedicated tare-and-interference corrections developed for the slender geometries representative of what will drive commercial supersonic aircraft designs. The aerodynamic results, analysis, and findings of the SCALOS project have been published and submitted to NASA. In parallel, motivated by the aeroelastic challenges facing slender, thin-wing, supersonic configurations, the second part of the dissertation presents active aeroelastic control studies that include analysis, synthesis of control laws, and wind tunnel aeroservoelastic demonstrations using two flexible high-aspect-ratio wing testbeds developed at the University of Washington, named MARGE and LARGE. The work covers gust load alleviation with preview H2 as well as H∞ control for active flutter suppression. For the active flutter suppression analysis and tests different flutter mechanisms were created by a destabilize/stabilize approach. Mixed-sensitivity H∞ robust control with modal damping was then used, focusing on closed-loop robustness, test/analysis correlation, and the experimental evaluation of readiness of the technology for implementation in actual flight vehicles. Together, these contributions add publicly accessible results and lessons that would contribute to the design and active aeroelastic control of the next generation of commercial supersonic aircraft.