Time-varying dynamic analysis of a plate entering the finite subsonic airflow field

Abstract

Devices entering rigid wall constrained finite airflow field are commonly seen in engineering practice. The devices gradually move from the infinite airflow field to the finite airflow field, which makes the device and the outside flow field a complicated time-varying fluid–structure interaction system. During the entry process, the stiffness, damping and mass of the devices change constantly over time, which makes the dynamic behaviors of the system show complex time-varying properties. Hence, it is needed to study the stability and vibration characteristics of the devices entering the finite airflow field. In this study, based on the von Karman nonlinear plate theory and the linear potential flow theory, the governing equation of the plate entering the finite airflow field is established by employing the Hamilton’s principle. By using the generalized eigenvalue method to linear system, the variations of the natural frequencies of the plate in the process of entering the finite airflow field are investigated, from which the stability change rules of the system are obtained. The vibration properties of the system are studied by analyzing the displacement time response of the plate in the process of entering the finite flow field. From the results, the different system parameters such as entry position, entry velocity, aspect ratio, external harmonic excitation amplitude and external harmonic excitation frequency have significant impacts on the stability and vibration properties of the plate entering the finite airflow field.