Global ETD Search
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 26 for “"Nonlinear simulations"”.
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Three-dimensional fully-nonlinear simulations of waves and wave body interactions
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1997.
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Study of directional ocean wavefield evolution and rogue wave occurrence using large-scale phase-resolved nonlinear simulations
… complex dynamic processes involved, including nonlinear wave interaction, wave breaking and wind forcing, and also wave interactions with currents and bottom bathymetry. With fast computational algorithms for nonlinear phase-resolved wave simulations and modern computational capabilities, we …
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Instabilities of an eastern boundary current with and without large-scale flow influence
… modes of an eastern boundary current can become nonlinearly unstable by resonating with short trapped unstable modes. This phenomenon is clearly demonstrated in the weakly nonlinear simulations. Results suggest that linearly stable longwave modes deserve more attention when the radiating …
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Instabilities of an eastern boundary current with and without Large-scale Flow Influence
… modes of an eastern boundary current can become nonlinearly unstable by resonating with short trapped unstable modes. This phenomenon is clearly demonstrated in the weakly nonlinear simulations. Results suggest that linearly stable longwave modes deserve more attention when the radiating …
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Barotropic Model Simulations of Low-Frequency Variability
Unforced, subcritical nonlinear simulations fail to produce meaningful variability, indicating that forcing is necessary in maintaining the low-frequency variability in the barotropic system under subcritical condition. Stochastically forced experiments are conducted using spatially homogeneous …
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Robust, model-based fault detection for commercial transport air data probes.
… flight condition using linear analysis and nonlinear simulations. Detection performance across the flight envelope is examined, and scheduling and blending techniques used to improve detection robustness across an expanded flight regime are explored.
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A strategy for modeling hydroelectric plants and improving their performance
… description. Guidelines for forming linear or nonlinear mathematical models are developed and the plan culminates in the determination of settings for P-I-D control which achieve optimum plant performance. Mathematical models are developed for the hydroelectric plant components -- the penstock, …
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CDGPS-based relative navigation for multiple spacecraft
… larger semimajor axis errors. These linear and nonlinear simulations also demonstrated the crucial role of the process noise in determining the semimajor axis knowledge. More sophisticated nonlinear models were included to reduce the propagation error in the estimator, but for long time steps …
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Modelling the human cochlea
… of the prevailing theories of SOAE generation. Nonlinear simulations of OAEs and the model’s response to various stimuli are performed in the time domain. Features observed in the model include the saturation of the forces generated by the OHCs, compression of amplitude growth with increasing …
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Robust decentralized control of power systems through excitation systems and thyristor controlled series capacitors
… In the first part an algorithm for the design of nonlinear decentralized excitation control is developed based on a feedback linearization technique. Feedback linearization technique is applied in excitation control of each generator to obtain an interconnected system where subsystems have linear …
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Novel PV Solar Farm Control as STATCOM (PV-STATCOM) for SSR Mitigation in Synchronous Generators and Wind Farms
… MATLAB based eigenvalue analysis validated by nonlinear simulations through SIMULINK and PSCAD software confirm the effectiveness of proposed SSR damping controls.
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Modeling and Control of Multi-Rotor UAVS: Design for Safety and Performance
… spot. Finally, the framework is tested via nonlinear simulations and results are presented.
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Turbulence and transport measurements in Alcator C-Mod and comparisons with Gyrokinetic simulations
… of intrinsic rotation in certain cases. Nonlinear simulations using the gyrokinetic turbulence code GYRO were performed using measured kinetic profiles from the dilution experiments both before and after the nitrogen seeding. The GYRO simulations reproduced the observed reduction in the …
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The effects of bronze and composite sleeves on trunnion yoke plate stress concentrations
Nonlinear simulations were used to predict and further understand the load transfer between trunnion shafts and yoke plates within a tainter gate trunnion assembly. Traditionally, yoke plates have been sized for an average stress based on the projected bearing area between the trunnion shaft and …
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Plasma turbulence in the equatorial electrojet observations, theories, models, and simulations
… characteristics of the two instabilities. Nonlinear simulations of the unified model of the equatorial electrojet instabilities reproduce many of the features that are found in radar observations and sounding rocket measurements under multiple solar and ionospheric conditions. The linear …
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Multiscale analysis of localized, nonlinear, three-dimensional thermo-structural effects
… cumbersome and prohibitively expensive numerical simulations for this class of problems. This study proposes a Generalized or eXtended Finite Element Method (G/XFEM) for analyzing three-dimensional solid, coupled physics problems exhibiting localized heating and thermomechanical effects. The …
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Mathematical and Computational Modeling of Injection-induced Seismicity
… carrying out a linear stability analysis and nonlinear simulations. We found that the likelihood of triggering earthquakes depends largely on the rate of increase in pore pressure rather than its magnitude. Thus, the model explains the common observation that abrupt increases in injection rate …
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On Data-Driven Modeling, Robust Control, and Analysis for Complex Dynamical Systems
… tools for robust control and analysis of complex nonlinear dynamical systems. Specifically, it leverages standard synthesis and robustness analysis techniques developed for linear systems and provides additional results to design robust controllers for nonlinear systems over the considered …
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Mars Precision Entry Vehicle Guidance Using Internal Moving Mass Actuators
… angle of attack range control commands. Nonlinear simulations of the entire 8 degree of freedom closed-loop systems demonstrate precision guidance to nominal trajectories and final targets for off-nominal initial entry conditions for flight path angle, range, cross-range, speed and …
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Brake-Actuated Steering of Heavy Goods Vehicles
… and high flow-rate emergency braking control. Simulations of the dual-flow braking system and of an improved pressure control strategy are developed and experimentally validated using a laboratory test-rig. In Chapter 3, nonlinear simulations of a tractor-semitrailer are developed and …
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