The Gravity Recovery and Climate Experiment (GRACE) primary mission will be performed by making measurements of the inter-satellite range change between two co-planar, low altitude, near-polar orbiting satellites. Understanding the uncertainties in the disturbance environment, particularly the aerodynamic drag and torques, is critical in several mission areas. These include an accurate estimate...

A simple approach for computing unsteady aerodynamic forces from simulated measured strain data is proposed in this study. First, the deflection and slope of the structure are computed from the unsteady strain using the two-step approach. Velocities and accelerations of the structure are computed using the autoregressive moving average model, on-line parameter estimator, low-pass filter, and a ...

in this paper, a nonlinear model of the underactuated six degrees of freedom (6 dof) quadrotor helicopter was derived based on the newton-euler formalism. a new nonlinear robust control strategy was proposed to solve the stabilizing and path following problems in presence of external disturbances and parametric uncertainties. the proposed control structure consist of a sliding mode control base...

The inclusion of smart devices in wind turbine rotor blades could, in conjunction with collective and individual pitch control, improve the aerodynamic performance of the rotors. This is currently an active area of research with the primary objective of reducing the fatigue loads but mitigating the effects of extreme loads is also of interest. The aerodynamic loads on a wind turbine blade conta...

The capacity for aerial maneuvering shaped the evolution of flying animals. Here we evaluate consequences of paravian morphology for aerial performance [1, 2] by quantifying static stability and control effectiveness of physical models [3] for numerous taxa sampled from within the lineage leading to birds (Paraves, [4, 5]). Results of aerodynamic testing are mapped phylogenetically [6, 7, 8, 9,...

To improve the low aerodynamic efficiency and reduce high energy consumption of a single-stage circulation control wing, multistage wing was designed. By combining force measurement particle image velocimetry (PIV), flow-field characteristics an aerofoil were investigated with respect to increase in number blowing slots, changes coefficient, different ratios for three slots. The results reveale...

Purpose The purpose of this study was to determine the validity of preliminary reports showing that glottal aerodynamic measures can identify pathophysiological phonatory mechanisms for phonotraumatic and nonphonotraumatic vocal hyperfunction, which are each distinctly different from normal vocal function. Method Glottal aerodynamic measures (estimates of subglottal air pressure, peak-to-peak...