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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 27 for “"strip-theory"”.
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Viscous flow around marine propellers using boundary layer strip theory
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1992.
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A strip theory approximation for wave forces on submerged vehicles in finite depth water
Autonomous Underwater Vehicles (AUV's) are becoming of increasing use in shallow waters for oceanographic data collection, coastal mapping, and military operations such as mine surveillance along enemy coastlines. Currently the control of AUV's in shallow water is very limited, largely due to a …
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A frequency domain strip theory applied to the seakeeping of the Zumwalt-Class destroyer
… was carried out in the framework of linear strip theory and potential flow. First, the problem was formulated and solved analytically. Second, a program called Ship Motions Analyzer (SMA) was written in MATLABTM to carry out the seakeeping analysis for regular waves in a discretized …
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Coaxial contrarotating twin rotor aerodynamics
… These equations are utilised with., conventional strip theory to enhance the predictive accuracy, and replace the arbitrary application of a tip loss factor. Using this combined approach, named Vortex-Strip theory, the full interference effects between the two rotors of a hovering CCTR have been …
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Multi-physics and Multilevel Fidelity Modeling and Analysis of Olympic Rowing Boat Dynamics
… potential flow simulation that is based on the strip theory approximation. These results show that due to the elongated shape of the boat, the use of Sommerfeld truncation boundary condition does not yield the correct frequency dependence of the radiative coefficients. Thus, the radiative forces …
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Identification of Finite-Degree-of-Freedom Models for Ship Motions
… predicting ship motions, including time-domain, strip-theory, and system-identification-based predictions. Time-domain and strip-theory predictions suffer from several physical and computational limitations. In this work, we use system-identification techniques to predict ship motions. We …
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Nonlinear Free Surface and Viscous Effects on Underwater Vehicle Maneuvering and Seakeeping
… by updating hydrodynamic derivatives using strip theory and boundary element method analysis. This new model can predict near-surface maneuvering motions of an AUV operating in calm or wavy waters. Alternative free surface affected motion predictions are offered by the Lagrangian Nonlinear …
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Integrated structural design, vibration control, and aeroelastic tailoring by multiobjective optimization
… problem. The use of quasi-steady aerodynamic strip theory with a thin-wall box beam model showed that the integrated design for a high aspect ratio, unswept, straight, isotropic wing can be separable. Finally, an efficient modal solution of the flutter equation facilitated the aeroelastic …
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Surrogate Models for Transonic Aerodynamics for Multidisciplinary Design Optimization
… by the MDO computational design environment. Strip theory is used to relate these two-dimensional results to the three-dimensional wing. Models are developed for the center of pressure location, the lift curve slope, the wave drag, and the maximum allowable lift coefficient before buffet. …
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Attitude control of an underwater vehicle subjected to waves
… operating in coastal waters and sea state 2. Strip theory is used to develop transfer function phase and magnitude between surface water waves and the slender body pitch, heave, and surge forces and moment for the vehicle in head seas, and for pitch, heave, yaw, and sway forces and moments in …
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Hydrofoil shape optimization by gradient methods
… dimensional effects. Prandtl's lifting line theory was used to account for induced drag and downwash at the leading edge of the foil. Strip theory was used to extend the two-dimensional wave drag solutions to three dimensions for high aspect ratio foils. A semi-empirical correction was added …
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Integrating seakeeping in the design of semi-displacement and displacement monohulls
… calculated by traditional methods such as strip theory due to the hydrodynamic effects that occur in the semidisplacement region. Traditional methods have a vessels' response in seas calculated after most initial design decision have been cemented, making changes in design for improved …
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An Underwater Explosion-Induced Ship Whipping Analysis Method for use in Early-Stage Ship Design
… model is derived using fundamental beam theory by representing the ship as a free-free beam with varying cross-sectional properties along its length. The fluid-structure interaction is approximated using strip theory and the distant flow assumption. The most severe predicted whipping load …
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Dynamics and Control of Flexible Aircraft
… the aerodynamic forces are derived by means of strip theory. The control forces for the flight dynamics problem are obtained by an "inverse" process. On the other hand, the feedback control forces for the extended aeroelasticity problem are derived by means of LQG theory. A numerical example …
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The application of advanced hydrodynamic analyses in ship design
… using parametrics and two-dimensional linear strip theory methods in the frequency domain. Model testing, due to its relative expense, is incorporated even later in the process. As a result, seakeeping performance is often evaluated after, rather than during, each stage of ship design. Serious …
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WEAKLY NONLINEAR DYNAMIC ANALYSIS OF FLOATING BODIES IN WAVES
… This study is based on a modified linear wave theory that gives a reasonable Froude-Krylov pressure distribution near the free surface. The idea of strip theory is then adopted to evaluate the Froude-Krylov force and the added mass and damping forces of the three dimensional floating body. The …
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Integral aerodynamic-structural-control wing design
… the span. The aerodynamic model is based on strip theory, and the control model is based on output feed-back control. With the structural-control interaction being the main focus, two different approaches are taken for the simplified wing design: (1) a sequential approach, (2) an integrated …
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An integrated approach to damage ship survivability assessment
… regarding intact ship hydrodynamics based on strip theory and Rankine source method (RSM). These are further utilised by convolution and spectral transformations in deriving relevant time domain force realisations. Non-linear excitation/restoring forces calculated from pressure integration up …
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Transonic flutter prediction and aeroelastic tailoring for next-generation transport aircraft
… for swept high-aspect ratio wings through strip theory and 3D corrections. The resulting low-order unsteady flow model is coupled to a typical-section structural model (for airfoils) or a beam model (for wings) to accurately predict utter of airfoils and wings. The method is fast enough to …
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Software for Multidisciplinary Design Optimization of Truss-Braced Wing Aircraft with Deep Learning based Transonic Flutter Prediction Model
… to verify the result obtained from extended Strip theory based aerodynamic analysis method. An approach is presented to develop a deep neural network (DNN)-based surrogate model for fast and accurate prediction of flutter constraints in multidisciplinary design optimization (MDO) of Transonic …
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