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Showing 1 to 17 of 17 for “"unsteady vortex-lattice"”.
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A numerical model of unsteady, subsonic aeroelastic behavior
A method for predicting unsteady, subsonic aeroelastic responses has been developed. The technique accounts for aerodynamic nonlinearities associated with angles of attack, vortex-dominated flow, static deformations, and unsteady behavior. The angle of attack is limited only by the occurrence of …
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Two-degree-of-freedom subsonic wing rock and nonlinear aerodynamic interference
… pitching and rolling motions and accompanying unsteady flowfield for a slender delta wing. The method uses a predictor-corrector technique in conjunction with the general unsteady vortex-lattice method to compute simultaneously the motion of the wing and the flowfield, fully accounting for the …
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Numerical simulations of wings in unsteady flows
The unsteady vortex-lattice method is used to calculate the pressure coefficients on thick and thin airfoils in steady and unsteady flowfields. The parameters which affect the results, such as time step and aspect ratio, are studied. The effects of Reynolds number and thickness of a wing in steady …
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A vortex-lattice method for Delta wing aerodynamics
… The lifting surface is modelled as a bound vortex sheet, while the wake is modelled as a force-free vortex sheet. The solution is obtained by the use of a unsteady Vortex-Lattice Method which includes the effect of leading edge separation. Numerical predictions for the aerodynamic loads and …
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Dynamical System Representation and Analysis of Unsteady Flow and Fluid-Structure Interactions
… utilized to reduce the representation order of unsteady fluid flows and fluid-structure interaction systems. This approach allows for significant reduction in the computational cost of their numerical simulations, implementation of optimization and control methodologies and assessment of their …
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Numerical Simulations of Interactions Among Aerodynamics, Structural Dynamics, and Control Systems
… performing numerical simulations of nonlinear unsteady aeroelastic behavior is developed. The technique is applied to long-span bridges and the wing of a modern business jet. The heart of the procedure is combining the aerodynamic and structural models. The aerodynamic model is a general …
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Hydrodynamic Study of Pisciform Locomotion with a Towed Biolocomotion Emulator
… proposes a reduced-order flow model using the unsteady vortex lattice method (UVLM) to predict the hydrodynamic performance of such a system. The proposed model is then validated with the experimental data collected earlier. The tool developed can be employed to quickly explore the possible …
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Shape and Structural Optimization of Flapping Wings
… response of the deformable wings. A linearized unsteady vortex lattice method is tightly coupled to a linear finite element model. The model is cost effective and the steady-state solution is solved by inverting a matrix. The aeroelastic model is used to maximize the thrust produced over one …
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Numerical Simulations of the Aeroelastic Response of an Actively Controlled Flexible Wing
… used for the simulations. A general, nonlinear, unsteady vortex-lattice method, which is capable of simulating arbitrary subsonic maneuvers of the wing and accounts for the history of the motion, is employed to model the flow around the wing and provide the aerodynamic loads. Two methods of …
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Numerical Wing/Store Interaction Analysis of a Parametric F16 Wing
… code comprised of ABAQUS/Standard and the Unsteady-Vortex-Lattice Method. Both codes communicate through an iterative handshake procedure during which displacements and air loads are updated. For each increment in time the force/displacement equilibrium is found in this manner. The wing, …
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Modeling and Analysis for Optimization of Unsteady Aeroelastic Systems
… the complex physics and dynamics associated with unsteady aeroelastic systems is often attempted with high-fidelity numerical models. While these high-fidelity approaches are powerful in terms of capturing the main physical features, they may not discern the role of underlying phenomena that are …
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Time-Domain Simulations of Aerodynamic Forces on Three-Dimensional Configurations, Unstable Aeroelastic Responses, and Control by Neural Network Systems
… found by the finite-element method. A general unsteady vortex-lattice method is used to provide aerodynamic forces. This method is verified by comparing the numerical solutions with the experimental results for several cases; and thereafter applied to several applications such as the …
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Neural-Network and Fuzzy-Logic Learning and Control of Linear and Nonlinear Dynamic Systems
… ship, whereas the fins are modeled by a general unsteady vortex-lattice method. The ship is considered to be a rigid body and the complete equations of motion are integrated numerically in the time domain. The motion of the ship and the complete flowfield are calculated simultaneously and …
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Numerical simulation of feedback control of aerodynamic configurations in steady and unsteady ground effects
… closely coupled lifting surfaces in steady and unsteady ground effects was developed. This model was coupled with the equations of motion to simulate aerodynamic-dynamic interaction. The resulting model was then coupled with a feedback-control law to form a general nonlinear unsteady numerical …
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Adaptive Control of an Aeroelastic System for Active Flutter Suppression and Disturbance Rejection
… problem. For the three-dimensional system, an unsteady vortex-lattice solver is implemented to calculate real-time unsteady aerodynamic forces and aerodynamic control force inputs. This is coupled with the flexible equations of motion to form the full aeroelastic equations of motion, which are …
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Flapping wings for dual aerial and aquatic propulsion
… using dye visualization, correlating the wake vortex structures with simultaneous force measurements. To inform the design space, I also analytically derive a low order state-space adaptation of the unsteady lifting line model for flapping or maneuvering wings of finite aspect-ratio. This …
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Modeling Analysis and Control of Nonlinear Aeroelastic Systems
Airplane wings, turbine blades and other structures subjected to air or water flows, can undergo motions depending on their flexibility. As such, the performance of these systems depends strongly on their geometry and material properties. Of particular importance is the contribution of different …