PECULIARITIES OF THE INTERACTION OF COMPRESSION JUMPS WITH FLUCTUATIONS OF AERODYNAMIC CONTROL SURFACES DURING THE OCCURRENCE OF TRANSONIC FLUTTER OF SUPERSONIC AIRCRAFT AND AEROSPACE SYSTEMS

The theoretical and experimental methods of classical (two-stage) flutter of aerodynamic surfaces in both stationary and non-stationary flows have been sufficiently developed.A large number of scientific works are devoted to the study of these oscillations. However, the problem of theoretical substantiation of the causes of intense oscillations of the aerodynamic control surfaces of supersonic aircraft at transonic flight speeds remains unsolved. There is still no universally accepted mathematical model of transonic flutter. The relevance of the solution to this problem is justified by the need for a preliminary assessment of the level of oscillations of aircraft structural elements before flight tests and the need to ensure reliable flight operation of supersonic aircraft and aerospace systems. In the article, based on the analysis of the regularities of the adiabatic expansion of the local supersonic flow on the surface of the aerodynamic profile and the mathematical model for estimating the excited hinge moments of the aerodynamic control surfaces, the conditions under which the occurrence of transonic flutter of the aerodynamic control surfaces of supersonic aircraft and aerospace systems is possible are determined. The analysis examined the characteristics of how sealing jumps interact with the oscillations of aerodynamic control surfaces in these flight modes, which determine the mechanism of transonic flutter of the aerodynamic control surfaces. It has been proved that the main reason for the intense oscillations of the aerodynamic control surfaces during the occurrence of transonic flutter is the phase advance of the movements of the sealing jumps along the profile of the aerodynamic control surface above the angle of its deviation, which is due to the angular velocity of the oscillations of the aerodynamic control surface. The main reason for the non-linear nature of the oscillations of the aerodynamic control surfaces during the occurrence of transonic flutter is the restriction of the movements of the sealing jumps along the profile of the aerodynamic control surface by both the rear and the front edges of the profile of the aerodynamic control surface. The obtained results can be used to predict the safe flight modes of supersonic aircraft and aerospace systems both at the stage of flight tests and the stage of operation.