The Local Flow Piston Theory-based Unit Fit Flutter Analysis Aeroservoelastic

This thesis focuses on the method for calculating supersonic and hypersonic unsteady aerodynamic force and aeroelastic analysis of complete aircraft, which are the requirements of the development of supersonic and hypersonic vehicle. The following works have been studied in this thesis.The CFD based local piston theory is further developed. The expressions are derived for downwash velocity of arbitrary curved surface and unsteady aerodynamic force of rotating fuselage and uncambered lifting surface by local piston theory. The local piston theory is further applied to calculating the unsteady aerodynamic force of three-dimensional lifting surface and rotating fuselage at angle of attack, which lay the foundations for flutter and aeroservoelastic analysis of complete aircraft. The validation test for obtaining local flow parameters by solving Euler and N-S equation is carried out by wind tunnel test of measuring the steady pressure distribution of a wing-body-tail configuration model.The rotating fuselage model and excitation equipment are designed for measurement of unsteady pressure in hypersonic wind tunnel. The method and result for calculating unsteady pressure distribution of rotating fuselage by CFD based local piston theory is validated by wind tunnel test with different Mach numbers and angles of attack.The complete set of methods and programs for flutter and aeroservoelastic analysis is built. The flutter boundary results by CFD based local piston theory agree with those by CFD/CSD direct coupling method, but the efficiency of CFD based local piston theory is much higher than CFD/CSD direct coupling method. The flutter characteristics of a wing-fuselage complete vehicle demonstrates that:flutter boundary reduce greatly with the increasing of angle of attack, especially at the high angle of attack; and monotonicities of flutter boundary of complex complete vehicle with several modes coupling may be different. The influencing factor of aeroservoelastic stability by changing the location of sensor is also researched, and the notch filter in series with system can improve the stability of system.