Improved aerodynamic mathematical models, for use in aircraft simulation or flight control design, are required when representing nonlinear unsteady aerodynamics. A key limitation of conventional aerodynamic models is the inability to map frequency and amplitude dependent data into the equations of motion directly. In an effort to obtain a more general formulation of the aerodynamic model, rese...

A method to efficiently generate a complete aerodynamic description for projectile flight dynamic modeling is described. At the core of the method is an unsteady, time accurate computational fluid dynamics simulation that is tightly coupled to a rigid body dynamics simulation. A set of n short time snippets of simulated projectile motion at m different Mach numbers is computed and employed as b...

This paper presents a time domain analysis framework for predicting nonlinear response of long-span bridges under turbulent winds. The nonlinear unsteady aerodynamic forces are modeled based on static force coefficients, flutter derivatives, admittance functions, and their spanwise correlations at varying angles of incidence. This analysis framework incorporates frequency dependent parameters o...

A reduced-order nonlinear unsteady aerodynamic modeling approach suitable for analyzing pitching/plunging airfoils subject to fixed or time-varying freestream Mach numbers is described. The reduced-order model uses kriging surrogates to account for flow nonlinearities and recurrence solutions to account for time-history effects associated with unsteadiness. The resulting surrogate-based recurre...

Unsteady flow models of wings and airfoils have been studied to understand the aerodynamic performance of natural flyers and provide improved maneuverability for micro aerial vehicles (MAVs). Vortex methods have been extensively applied to reduce the dimensionality of these aerodynamic models, based on the proper estimation of the distribution and evolution of the vortices in the wake. In such ...

AD-P004 168 AD-P004 169 TITLE: Superroaneuverability. Wing Rock Flov Phenomena. Potential Applications of Forced Unsteady Flows. Unsteady Stall Penetration of an Oscillating Swept Wing. Simultaneous Flow Visualization and Unsteady Lift Measurement on an Oscillating Lifting Surface. A Visual Study of a Delta Wing in Steady and Unsteady Motion. Comparative Visualization of Accelerating Flow aroun...

Traditionally, the estimation of wind induced buffeting response and analysis of flutter instability have been conducted in the frequency domain utilizing linear approaches. These approaches are limited to linear structures in which nonlinearities in aerodynamic forces are ignored. In this study, a time domain analysis framework for predicting the flutter and buffeting responses of bridges unde...

This paper responds to research into the aerodynamics of flapping wings and to the problem of the lack of an adequate method which accommodates large-scale trailing vortices. A comparative review is provided of prevailing aerodynamic methods, highlighting their respective limitations as well as strengths. The main advantages of an unsteady aerodynamic panel method are then introduced and illust...