Validation of theoretical aerodynamic models of a pitching thin plate in various periodic gusts

The aerodynamic characteristics of a pitching flat plate encountering periodic gusts represent a fundamental problem in the field of aerodynamics and have motivated the development of theoretical gust-loading models. However, experimental validation of these models remains challenging, as it requires specialized facilities such as the active gust generator and forced-vibration system. Therefore, numerical methods that allow precise control of prescribed gust inflows and pitching motion are needed as a useful complement to experimental approaches. Aiming to validate the theoretical aerodynamic models and clarify the gust–motion interactions, this study investigates the unsteady lift and moment of a pitching flat plate in various periodic gusts using Unsteady Reynolds-averaged Navier–Stokes (URANS) simulations. Three types of periodic gusts in longitudinal, vertical, and bidirectional directions are synthetically generated to validate the Greenberg theory, the combined Theodorsen–Sears theory, and the combined Greenberg–Sears theory, respectively. Nine gusty inflow cases are considered to examine the effects of pitching amplitudes and gust characteristics on aerodynamic components and flutter derivatives (FDs). The URANS results match all three theoretical models at small pitching amplitudes. However, significant deviations occur at larger pitching amplitudes, particularly as increased vertical gust intensity breaks up the leading-edge vortices and generates strong secondary vortices, which in turn shift the phase of motion-induced moment and reverse the critical FD A2* from positive to negative. This study provides guidance for numerical simulations and aerodynamic models of an oscillating body subjected to gusts.