Oblique Flying Wing Aerodynamic Design And Flight Dynamics Of A Preliminary Study

During the past three decades aviation industries have tried to design a supersonic cruise aircraft, especially a supersonic transport. Aviation institutions are attending many theoretical study and experiments, and have received some results and design experiences. As a choice of high-speed aircraft type, Oblique wing aircraft receives much attention and investigation, included wind tunnel experiments and numerical simulation. Based the results studied previously, this thesis primarily analyses oblique wing technique, especially investigates the subsonic and supersonic aerodynamic characteristics of oblique flying wing (OFW).In theory, oblique elliptic wing with an elliptic load has the minimum wave drag due to lift and induced drag. The institutions pay much attention to it stemmed from the fact. Oblique wing aircraft can decrease high transonic and low supersonic flight drag, and improves the aerodynamic efficiency in high speed flight. Another significant advantage of oblique-wing aircraft is as a role of variable sweep aircraft. The feature permits to maximize aerodynamic performance over a wide range of speeds. In despite of these technique advantages, the asymmetrical-swept led to the strong aerodynamic and inertial couplings, which have adverse effects on flight dynamics and flight control. These challenges are especially formidable for all-wing configurations that lack the powerful stability and control contributions from traditional tails. The thesis discusses some important aspects of aerodynamic design of OFW dealing against unusual aerodynamic and dynamic characteristics of OFW, which contain optimal oblique sweep, airfoil design, asymmetrical planform design, bending and twisting the wing alone the wing span and so on.A transport OFW concept is designed referred to relational researches. The thesis calculates and discusses the subsonic and supersonic aerodynamic characteristics of the OFW concept. In supersonic case, 3D Euler equations are solved using Cartesian grid; in subsonic case, inviscid aerodynamic coefficients are computed by steady potential fluid Greens Function Method, viscid drag is calculated by empirical formula. The results indicate OFW has relatively high supersonic aerodynamic performance, and asymmetrical forces and moments are effectively diminished according to proper aerodynamic design. When OFW's sweptwards angle appropriately altered due to flight speed, OFW also has excellent aerodynamic efficiency. The aerodynamic shape designed corresponding to supersonic design point brings rarely adverse influence in low-speed and subsonic case. The study results discussed above show the application forest of oblique flying wing is expected.Asymmetrical OFW inherent aerodynamic and inertial couplings make its flight dynamic system different from that of conventional symmetrical aircraft. Small perturbation six DOF equations of motion are derived in the paper. Based upon the EOM, flight dynamic characteristics including dynamic stability and response can be analyzed, and process flight control law design.