Large-eddy simulations are performed to investigate the dynamic response of a natural laminar flow airfoil undergoing harmonic small-amplitude pitch oscillations at a chord based Reynolds number of . Large changes in the transition location as well as trailing-edge separation are observed throughout the pitch cycles, which leads to a nonlinear response of the aerodynamic forces. Despite the highly nonlinear nature of the flow, the evolution of the boundary layer over the airfoil can be modeled by using a simple phase-lag concept, which suggests a quasi-steady evolution of the boundary layer. A simple empirical model is developed based on this phase-lag assumption, which fits very well with the measured experimental data and identifies the primary source of non-linearities in the unsteady aerodynamic forces.
Unsteady Response of Natural Laminar Flow Airfoil Undergoing Small-Amplitude Pitch Oscillations
AIAA Journal ; 59 , 8 ; 2868-2877
2021-05-06
10 pages
Article (Journal)
Electronic Resource
English