Modeling of Wing Drag Reductions Due to Structural Dynamics in Atmospheric Gusts

Recent research interests explore the use of the energy present in atmospheric gusts for drag reduction of small and medium sized uninhabited airborne vehicles. Many approaches use active control systems that detect and make use of energy is present in of atmospheric disturbances. A different, passive approach to make use of the energy of atmospheric gusts can be accomplished with an aircraft-wing structure whose structural dynamics are aeroelastically tailored. Previous studies have shown that significant drag reductions, up to 30 percent, are possible even with zero-mass net-motion gusts. However, due to simplified analysis, a detailed investigation is needed to justify these claims. Various responses were analyzed using coupled aerodynamic and structural dynamic simulations in drag reduction verification. The aerodynamic simulation is based on a potential flow model that uses distributed vorticity elements. The structural dynamic simulation uses an explicit finite difference numerical model of the coupled dynamics of the time-dependent Euler-Bernoulli equation for thin beams in non-symmetrical bending and the time-dependent torsion equation for non-circular cross-sections. The aerodynamic model uses distributed vorticity elements that model the bound circulation in a continuous fashion