Natural Rolling Responses of a Delta Wing in Transonic and Subsonic Flows

The unsteady, three-dimensional, full Navier-Stokes (NS) equations and the Euler equations of rigid-body dynamics are sequentially solved to simulate the natural rolling response of slender delta wings of zero thickness at moderate to high angles of attack, to transonic and subsonic flows. The governing equations of fluid flow and dynamics of the present multi-disciplinary problem are solved using the time-accurate solution of the NS equations with the implicit, upwind, Roe flux-difference splitting, finite-volume scheme and a four-stage Runge-Kutta scheme, respectively. The main focus is to analyze the effect of Mach number and angle of attack on the leading edge vortices and their breakdown, the resultant rolling motion, and overall aerodynamic response of the wing. Three cases demonstrate the natural response of a 65 deg swept, cropped delta wing in a transonic flow with breakdown of the leading edge vortices and an 80 deg swept delta wing in a subsonic flow undergoing either damped or self-excited limit-cycle rolling oscillations as a function of angle of attack. Comparisons with an experimental investigation completes this study, validating the analysis and illustrating the complex details afforded by computational investigations

Flapping and Flexible Wing Aerodynamics of Low Reynolds Number Flight Vehicles

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76905/1/AIAA-2006-503-331.pd

FEDSM2006-98559 HIGH-ORDER COMPUTATIONAL TECHNIQUES FOR UNSTEADY VORTICAL FLOWS OVER DELTA WINGS

ABSTRACT Introduction Delta-like wings are a common design feature of many aircraft including currently proposed unmanned combat air vehicles, micro air vehicles and high-performance fighter aircraft. The complex flows over these types of aircraft when maneuvering involve massive separation and place numerous demands on a computational method. The flowfields are inherently unsteady and three-dimensional. Because of the abrupt nature of the onset of vortex breakdown and the extreme sensitivity of performance coefficients (e.g., pitching moment coefficient, rolling moment coefficient) to the proper representation and location of breakdown, a high degree of accuracy is required to satisfactorily compute these challenging unsteady flowfields. In order to effectively predict these types of highly nonlinear flows a computational approach that solves the unsteady, threedimensional Navier-Stokes equations using a well-validated and robust high-order solve