Post-stall flight dynamics of commercial transport aircraft configuration: A nonlinear bifurcation analysis and validation

Abstract

Loss-of-control has become the largest fatal accident category for worldwide commercial jet accidents, and any initiative aimed at preventing such events requires an understanding of the fundamental aircraft behavior, especially the flight dynamics at post-stall region at which loss-of-control usually occurred. A series of low-speed static and dynamic wind tunnel tests of the Common Research Model over a large angle of attack/sideslip envelope was conducted and a non-linear aerodynamic model was developed. The bifurcation analysis, complemented by time-history simulation was used to understand the post-stall flight dynamics and the numerical analysis results were preliminary validated by wind tunnel virtual flight test. Several representative post-stall behaviors for the transport aircraft have been identified, including departure, periodic oscillation, post-stall gyration and steep spiral, etc. Furthermore, the predicted periodic oscillation in pitch motion has been perfectly duplicated in wind tunnel virtual flight test. The approach used in this work shows a promising way to uncover the flight dynamics of transport aircraft at extreme and loss-of-control flight conditions, as well as to apply to nonlinear unsteady aerodynamics modeling and validation, flight accident investigation, advanced flight control law design or studying initiative for loss-of-control prevention or mitigation.

Underconstrained Cable-Driven Parallel Suspension System of Virtual Flight Test Model in Wind Tunnel

“…Zhao et al [2] of the China Aerodynamics Research and Development Center used a hanger model support system in a transonic wind tunnel with the length of 2.4 m to realize model pitch and roll free motion as well as yaw-driven control motion, and examined the aerodynamic/motion coupling mechanism; Hao studied the criterion and simulation method similar to WTB-VFT [14]; Guo et al [15] used a contacted ball hinge support mechanism with three degrees of freedom, a support mechanism with three degrees of freedom that includes a universal hinge of two degrees of freedom, and a rotating curved rod to study the dynamics [16,17]; Cen et al [18][19][20] also conducted research on technologies related to model free-flight tests and VFT. Additionally, the Nanjing University of Aeronautics and Astronautics [21,22], AVIC Aerodynamics Research Institute [23], and China Academy of Aerospace Aerodynamics [23] have conducted related research.…”