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Showing 1 to 20 of 45 for “"Aerodynamic Model"”.
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A Low Order Aerodynamic Model of Embedded Total Temperature Probes
… probe. In order to support this development, a model was desired to be developed that accurately modelled the recovery using a low-order analysis that could be implemented quickly. The creation and validation of such a model is the primary focus of the present research. Of secondary interest is …
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An Aerodynamic Model for Use in the High Angle of Attack Regime
… aircraft using the Dynamic Plunge--Pitch--Roll model mount at Virginia Tech Stability Wind Tunnel are described. Corresponding data reduction methods are developed on the basis of multirate digital signal processing. Since the model is sting mounted, the frequencies associated with sting …
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Identification of an Unsteady Aerodynamic Model up to High Angle of Attack Regime
… using the Dynamic Plunge-Pitch-Roll (DyPPiR) model mount at Virginia Tech Stability Wind Tunnel are described and analyzed. The corresponding data reduction methods are developed on the basis of multirate digital signal processing techniques. Since the model is sting-mounted to the support …
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Implementation of Constrained Control Allocation Techniques Using an Aerodynamic Model of an F-15 Aircraft
… Allocation techniques are discussed, and an aerodynamic model of a highly modified F-15 aircraft is used to demonstrate the various aspects of Constrained Control Allocation. This work was conducted under NASA research grant NAG-1-1449 supervised by John Foster of the NASA Langley Research …
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Analysis of the dynamic stability derivatives for high angle of attack aircraft
… flight regime it is necessary to have a proper aerodynamic model. Flight conditions at high angles of attack lead to separated flows making the aerodynamic model more difficult to obtain. In this research wind tunnel experiments are performed on an F-5 air-craft model at high angles of attack, …
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Aerodynamic Parameter Identification of a Venus Lander
… was conducted to identify the parameters of an aerodynamic model for a Venus lander based on experimental free-flight data. The experimental free-flight data were collected in the NASA Langley 20-ft Vertical Spin Tunnel with a 25-percent Froude-scaled model. The experimental data were classified …
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Numerical simulation of wakes, blade-vortex interaction, flutter, and flutter suppression by feedback control
A general aerodynamic model for two-dimensional inviscid flows is developed. This model is used to simulate wakes and blade-vortex interaction. This model is also coupled with dynamics and feedback controls to simulate flutter and flutter suppression. The flow is assumed to be attached and …
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Adaptive, suboptimal and nonlinear control of an aeroelastic system
… a nonlinear aeroelastic system. The aeroelastic model describes the plunge and pitch motion of a wing. The model includes plunge and pitch nonlinearties, and has a single control surface for the purpose of control. First an output feedback modular adaptive control system is derived. Quasi-steady …
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Vibration and Aeroelasticity of Advanced Aircraft Wings Modeled as Thin-Walled Beams--Dynamics, Stability and Control
… refined analytical anisotropic thin-walled beam model, aeroelastic instability, dynamic aeroelastic response, active/passive aeroelastic control of advanced aircraft wings modeled as thin-walled beams are systematically addressed. The refined thin-walled beam model is based on an existing …
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Identification of Unsteady Flight Dynamic Models and Model-based Wind Estimation with Flight Test Validation
Numerical weather modeling can benefit from improved wind sensing in the Earth's atmospheric boundary layer (ABL). Small, low-cost, uncrewed aircraft (drones) can be used to measure wind and a distribution of these vehicles could potentially provide measurements with much greater density and …
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Optimizing American Football Kickoffs
… and angle that minimizes the field position, an aerodynamic model for the ball trajectory and a biomechanical model for running players was used. The model confirmed that kicking the ball at a higher angle and at a higher velocity is better as long as the ball doesn't go into the endzone for a …
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A Numerical Vortex Approach To Aerodynamic Modeling of SUAV/VTOL Aircraft
A combined wing and propeller model is presented as a low-cost approach to preliminary modeling of slipstream effects on a finite wing. The wing aerodynamic model employs a numerical lifting-line method utilizing the 3D vortex lifting law along with known 2D airfoil data to predict the lift …
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Passenger comfort during formation flight within atmospheric turbulence
… in discomfort, a simple formation flight aerodynamic model for two aircraft in formation was developed. The wing trailing vortices were assumed to shift in an ideal fashion within atmospheric turbulence resulting in aerodynamic disturbance loads acting on the trailing aircraft. As the …
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An Invariant Extended Kalman Filter for Indirect Wind Estimation Using a Small, Fixed-Wing Uncrewed Aerial Vehicle
… wind estimation methods are classified as model-based or model-free, where the model refers to the aerodynamic force and moment model of the considered aircraft. The invariant EKF is designed for aerodynamic model-free wind estimation using a fixed-wing UAV in horizontal-plane flight and …
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A vortex panel method for potential flows with applications to dynamics and controls
… for potential-flow is developed. The surface is modeled as a collection of triangular elements on which the vorticity vector is piecewise linearly varying. The wake emanates from the sides and trailing edges of the thin lilting surfaces and is modeled as a progressively formed collection of …
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Aeroelastic Modeling of Blade Vibration and its Effect on the Trim and Optimal Performance of Helicopter Rotors using a Harmonic Balance Approach
… higher</p><p>harmonic controls. A nite element model is introduced to model the structural</p><p>eects of the blade, and a coupled induced velocity/projected force model is used</p><p>to couple this structural model to the aerodynamic model constructed in previous</p><p>works. The system is then …
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Optimization study of a trans-Atlantic abort for the U.S. space shuttle using a pseudospectral Legendre method
… flight, and each phase has a different dynamic model governing the motion of the vehicle. To ensure a solution is obtained for each abort, additional constraints on the vehicle are formulated as soft constraints in the penalty function. In particular, the third phase cost functional consists of …
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Computational aspects of the integrated multi-disciplinary design of a transport wing
… system involving the complete interaction of aerodynamics and structural mechanics. Critical to this design process, is the ability to accurately and efficiently calculate the sensitivities of the involved quantities (such as drag and dynamic pressure) with respect to the design variables. …
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Development and Deployment of a Dynamic Soaring Capable UAV using Reinforcement Learning
… in Surfaces was employed to build a complete aerodynamic model of the UAV. Deep deterministic policy gradient (DDPG), an actor-critic RL algorithm, was used to train a closed-loop Path Following (PF) agent and an Unguided Energy- Seeking (UES) agent. Several generations of the PF agent were …
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System Identification of a Nonlinear Flight Dynamics Model for a Small, Fixed-Wing UAV
… the development of a nonlinear flight dynamics model for a small, fixed-wing unmanned aerial vehicle (UAV). Models developed for UAVs can be used for many applications including risk analysis, controls system design and flight simulators. Several challenges exist for system identification of …
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