Aerodynamic Modeling of Lifting Surfaces Accounting for Synthetic Jet Actuators

摘要

This paper contributes to the development and validation of reduced order unsteady aerodynamic models of lifting surfaces accounting for Synthetic Jet Actuation (SJA). SJAs located within a lifting surface have the ability to manipulate the nearby airflow making them very attractive for a number of applications, in particular flow separation and aeroelastic control. Recent results have shown that SJAs can allow lifting surfaces to carry loads without flow separation at much higher angles-of-attack then the counterpart without jet actuation. In addition, even at small angle-of-attack, the actuators energize the flow in the boundary layer, directly contributing to the airfoil "dynamic virtual shaping" that enhances the performance of the lifting surface. The flow structure of a lifting surface with a SJA is quite complicated and so far the characterization of such structure, at all scales, has been done primarily by means of CFD computations or experiments. However, when the interest is limited to the determination of global aerodynamic properties, that is, unsteady aerodynamic lift and moment, it is possible to characterize the flow around the lifting surface with SJAs through reduced order models (ROMs). This paper extends a prior effort of the authors, providing a better understanding of the validity of two ROMs: the Unsteady Theodorsen's based SJA Model (T-SJA) and the Unsteady Doublet Panel SJA Model (UDP-SJA). To validate the T-SJA and the UDP-SJA models, CFD have been employed. A number of parameters, such as airfoil thickness, jet location and frequency of actuation will be considered for a static airfoil at zero angle-of-attack. This parameter space enables one to estimate the region in which ROMs are valid. In addition, this paper aims to extend the validity of such ROMs as to account for thickness effects as well as to empirically correct the aerodynamic loads for positions of the jet toward the leading and trailing edges, where ROMs could potentially break down.