Stability Analysis Of Panel In Subsonic Flow

With the increasing velocity of high-speed train, the instability of outer panel skin and window structure in high-speed train under aerodynamic pressure is more and more concerned by people. The velocity of high-speed train is basically in the low-subsonic range, and approximately equals 0.3 Mach number. In order to research the stability of the panel structures of high-speed train, the aerodynamical panel models in subsonic flow are set up, and the differential quatrature method(DQM) is used to discrete the governing motion equations into a series of ordinary differential equations, which are calculated by the self-complied program based on MATLAB. The eigenvalue method is used to analyze the instability characteristics of the panels. The main works of this paper are shown as follow:1. By means of potential flow theory, the approximate analytic expression of aerodynamic forces acting on the panel is obtained, which is simplified and combined with the governing motion equation of the two-dimensional panel with spring-spring supports. The corresponding discrete forms of the continuation equation of the panel are obtained by DQM. The eigenvalue method is applied to study the stability of the panel, the results of which show that there is flutter phenomenon in the two-dimensional panel with spring support at both ends, and the critical flutter aerodynamic pressure is influenced by spring stiffness and mass ratio.2. The instability of the three-dimensional panel with simple supports in subsonic flow, which has arbitrary flow angle, is studied. The analytic expression of aerodynamic forces of subsonic flow with flow angle is derived and combined with the governing motion equation of the panel. The discrete form of coupled equations is obtained by differential quadrature method. The form of instability of the panel is divergence, judged by the eigenvalue method. The effects of flow angle, in-plane loading, length-width ratio and mass ratio on the natural frequencies and the critical aerodynamic pressure of the panel bucking are discussed.3. The three-dimensional panels with spring supports and damping-spring supports in subsonic flow are studied. When disposing the damping boundary conditions, a measure similar to the 5 method is used, and the damping constraints are applied in the outer layer of inner discrete grid points. The flutter phenomenon is observed in the three-dimensional panel with both boundary conditions, and the relationship between the critical flutter aerodynamic pressure and the system parameters such as spring stiffness, damping, and flow angle is discussed.