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 44 for “"Wave interaction"”.
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Shock wave interaction in a tee junction
The problem was to determine the unsteady shock wave interaction at a tee junction, and to measure the transmitted shock strength. Two tee junctions of different cross-sectional shape were constructed, and instrumented with three piezoelectric pressure transducers and two hot wire anemometers. …
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Planar shock wave interaction with a multiphase cylinder
… camera, that an instability occurs as the shock wave bypasses the slow-moving column of gas. This produced evident perturbation at the interface. The flow morphology of the gas column consists of a pair of counter-rotating vortices that develops downstream from the initial conditions as well as …
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Spatiotemporal chaos in the nonlinear three wave interaction
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 1992
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ISPH Modelling of Solitary Wave Interaction with Permeable Beaches
… such as storm surges and tsunamis. Dykes, wave-absorbing blocks, and forests, are typical solutions to mitigate coastal disasters. In coastal engineering, these protections and beaches are considered as porous media. Accurate prediction of wave motion around porous structures is necessary …
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MPM study of water wave interaction with porous seawalls
… from rising sea levels and storm surge waves. Waves attenuate rapidly as they propagate through porous media, corresponding to significant energy dissipation. The ability of porous armour layers to absorb wave energy is therefore of great interest to hydraulic engineers, as more and more …
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A Theoretical and Numerical Study of Turbulent Wind-Wave Interaction
A deep understanding of turbulent wind-wave interactions is critical for many applications, such as weather modeling in the marine environment, navigation safety of marine vehicles, and offshore wind energy harvesting. The present understanding of the fundamental flow dynamics underlying wind-wave …
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Shock wave interaction with a fluid filled cylinder experimental methods
… devices (IED's). Whether pure blast-shock waves cause TBI or what is the mechanism of injury are not fully known. Research efforts are underway to find answers to these questions. The primary objective of this project is to understand how the shockwave interacts with a fluid-filled cylinder …
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Planar and oblique shock wave interaction with a droplet seeded gas cylinder
We present an experimental study of a shock interaction with an initially diffuse heavy-gas cylinder seeded with submicron-scale glycol droplets. Unlike most earlier studies, the investigation covers not just a quasi-two-dimensional geometry, where the axis of the cylinder is parallel to the plane …
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Stochastic electron trajectories and wave interaction in relativistic gyro-traveling wave amplifiers
Gyro-traveling-wave amplifiers (gyro-TWAs) are types of gyrodevices, which take advantage of the cyclotron maser instability to produce coherent electromagnetic (EM) radiation from electrons gyrating in an external magnetic field and interacting with fast traveling waves. For high power …
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Second Harmonic Generation Stimulated Electromagnetic Emissions during High Power High Frequency Radio Wave Interaction with the Ionosphere
The interaction of a high power, high frequency (HF) pump/electromagnetic (EM) wave transmitted from a ground-based station with the ionosphere, experiments which have been termed "ionospheric heating", produces secondary radiation known as stimulated electromagnetic emissions (SEEs). SEEs have …
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Fundamental Studies In the Lamb-Wave Interaction Between Piezoelectric Wafer Active Sensor and Host Structure During Structural Health Monitoring
… of the engineering variables that influence the interaction of PWAS with structure during activation of the transducer. This is a key feature needed to develop more power/energy efficient structural health monitoring (SHM) systems. SHM is the field of engineering that determines the health of a …
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Non-linear propagation of waves on two-dimensional liquid sheets
… behavior of antisymmetric as well as symmetric waves on a two-dimensional liquid sheet is studied, the effects of the surrounding fluid being taken into account. The non-linear Schrödinger equation governing the wave motion is derived by the method of multiple scales. Modulatory stability, …
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Metamaterial structures for Wakefield acceleration and high power microwave generation
… and experimental investigation of the interaction of metamaterial structures with electron beams for two applications: wakefield acceleration and high power microwave generation. Under the topic of wakefield acceleration, on the theoretical side, several metamaterial structures have …
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Analysis of Kelvin-Helmholtz Instabilities Developing from Oblique Shock Interaction with a Heavy Gas Column
… of instabilities developing from oblique shock wave interaction with a heavy gas column. For these experiments, the gas column consists of pure sulfur hexafluoride infused with ~11% acetone gas by mass. A misalignment of the pressure and density gradients (from the shock wave) results in …
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Evolution of atmospheric baroclinic waves
The evolution of atmospheric baroclinic waves is investigated by a six-layer forced dissipative quasi-geostrophic $\beta$-plane channel model. In the control run, the model has: (i) a realistic zonal thermal forcing, (ii) a surface Ekman layer, a Newtonian cooling and an interior biharmonic …
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The effect of internal waves on long range acoustic propagation in the ocean
The acoustic-internal wave interaction in an acoustic waveguide is investigated using wave techniques. Refractive index fluctuations due to the vertical displacements of the internal waves create an inhomogeneous waveguide. The analysis uses weak scattering theory based upon the Rytov perturbation …
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Analysis of the sensing region of a PZT actuator-sensor
… of this technique is possible. Thereby, a wave propagation continuum mechanics based approach has been applied to model the high frequency vibrations of one dimensional structures. Energy dissipation mechanisms, such as bolted connections and internal friction, are considered to have a …
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Integrable Evolution Partial Differential Equations: Multidimensions and Dirichlet-to-Neumann Maps
… applications, including the theory of water waves and optics. The thesis focuses on two main topics: A. Solving multidimensional integrable PDEs The modern history of integrable systems begins in the late 1960’s when Gardner et al. solved the initial value problem of the Korteweg-de Vries …
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Seismic Modeling and Imaging for Detection of Clandestine Tunnels
… In our modeling, we use the elastic full-wave finite-element method to simulate seismic wave interaction with subsurface tunnels. We test different frequencies and observational geometries including surface and borehole sources and receivers. We then used the modeled seismic data to …
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Two-dimensional periodic surface lattice high power millimetre wave experiment
Millimetre wave radiation generation from a free electron maser based on a two-dimensional (2D) periodic surface lattice has been demonstrated. Second harmonic Gyrotron Backward Wave Oscillator (BWO) interaction with a two dimensional periodic surface lattice (PSL) has been observed. The major …
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