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On short-crested water wavesMarchant, Timothy Robert. January 1988 (has links) (PDF)
Typescript. Bibliography: leaves 145-150.
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Numerical modeling of landslide-induced waves and their effects on downstream structuresLiu, Xia, 刘霞 January 2012 (has links)
Impulse waves in reservoirs, lakes, bays and oceans may be generated by
landslides. The resulting impulse waves can propagate and cause disaster to the
downstream. Some studies are carried out to investigate such phenomenon but
most of them were based on either experimental observations or empirical/semiempirical
relationships in simulating the waves generated by landslides. Therefore,
the fundamental mechanism of such hazard is not got fully understood (complex
motions of landslides with arbitrary geometry and interactions of fluid with
landslides or shorelines). In addition, the effects of landslide-induced waves on
downstream structures are rarely reported. Therefore, it appears necessary that the
coupling numerical model is developed to simulate landslide-induced waves and
to investigate generated wave characteristics. Furthermore, their effects on
downstream structures should be investigated for mitigating hazard, such as the
estimations of wave run-up, rundown and wave overtopping.
This thesis presents the numerical modeling of landslide-induced waves and their
effects on the downstream structures based on the computational fluid dynamics
(CFD) package FLUENT. As there is no existing module to simulate water waves,
the redevelopment of FLUENT by the user defined function (UDF) is necessary.
For the problem of landslide-induced wave, two simplified numerical models are
developed, including piston-type model and inlet boundary-type model. These two
numerical models can rapidly assess the landslide-induced waves but be
appropriate for the simple cases, such as a vertical wall moving horizontally or
slump-type landslide whose particle velocities and free surface displacements at
the inlet boundary are known. In order to expand the available range of numerical
modeling, the block models aiming for rockslide are developed to investigate
landslide-induced waves. Four categories of landslides are considered, such as
horizontal landslide, vertical landslide, subaerial landslide and submarine
landslide. Except of horizontal landslide, the coupled block model is employed to
investigate water waves generated by vertical, subaerial and submarine landslides.
The coupling is based on an iterative procedure enforcing the principle of the
dynamic equilibrium of the fluid, the slide and their interfaces, and the interaction
between landslide and fluid are considered. The wave characteristics generated by
above-mentioned different types of landslides are investigated and discussed. For
their effects of landslide-induced wave on downstream structures, the focuses of
numerical modeling are the run-up and rundown of waves generated by subaerial
and submarine landslides and wave overtopping on the downstream structures.
The detailed numerical modeling illustrates that the present models can predict
fairly well landslide-induced waves and their effects on downstream structures.
The results of parametric study indicate that slide volume and impact Froude
number ( v / gh ) play important roles on generated wave characteristics. The
wave characteristics, propagation distance and geometric characteristics of
seaward structural wall (slope and crest freeboard) are major factors in
determining the characteristics of wave run-up, rundown and overtopping. Several
useful prediction relationships are provided. / published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy
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Fractal solutions to the long wave equationsAjiwibowo, Harman 13 September 2002 (has links)
The fractal dimension of measured ocean wave profiles is found to be in the
range of 1.5-1.8. This non-integer dimension indicates the fractal nature of the
waves. Standard formulations to analyze waves are based on a differential
approach. Since fractals are non-differentiable, this formulation fails for waves with
fractal characteristics. Integral solutions for long waves that are valid for a non-differentiable
fractal surfaces are developed. Field observations show a positive
correlation between the fractal dimension and the degree of nonlinearity of the
waves, wave steepness, and breaking waves. Solutions are developed for a variety
of linear cases. As waves propagate shoreward and become more nonlinear, the
fractal dimension increases. The linear solutions are unable to reproduce the change
in fractal dimension evident in the ocean data. However, the linear solutions do
demonstrate a finite speed of propagation.
The correlation of the fractal dimension with the nonlinearity of the waves
suggests using a nonlinear wave equation. We first confirm the nonlinear behavior
of the waves using the finite difference method with continuous function as the
initial condition. Next, we solve the system using a Runge-Kutta method to
integrate the characteristics of the nonlinear wave equation. For small times, the
finite difference and Runge-Kutta solutions are similar. At longer times, however,
the Runge-Kutta solution shows the leading edge of the wave extending beyond the
base of the wave corresponding to over-steepening and breaking.
A simple long wave solution on multi-step bottom is developed in order to
calculate the reflection coefficient for a sloping beach. Multiple reflections and
transmissions are allowed at each step, and the resulting reflection coefficient is
calculated. The reflection coefficient is also calculated for model with thousands of
small steps where the waves are reflected and transmitted once over each step. The
effect of depth-limited breaking waves is also considered. / Graduation date: 2003
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Flexible membrane wave barrierThompson, Gary O. 02 May 1991 (has links)
This report details the derivation of an analytical model for a flexible membrane
wave barrier. The wave barrier consists of a thin flexible membrane suspended in the
water column by a moored cylindrical buoy on the free surface and fixed to a hinge at
the seafloor.
The analytical model combines the three-degree of freedom rigid body motion
of the cylindrical buoy with the two-dimensional analog of a vibrating string for the
response of the flexible membrane. Theoretical results for reflection and transmission
coefficients, dynamic mooring line tension, horizontal hinge force, horizontal and
vertical displacements and rotation of the cylindrical buoy are compared with measured
results presented by Bender(1989).
In general, the theoretical results compare favorably with measured results for
moored systems. However, additional studies are required to more precisely quantify
the added mass and radiation damping properties of flexible membranes in oscillating
flows. / Graduation date: 1991
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A computational procedure for three-dimensional simulation of nonlinear gravity wave propagation and response of floating structuresHardjanto, Fauzi Adi 16 May 2011 (has links)
Not available / text
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The propagation of nonlinear waves in layered and stratified fluidsLai, Wing-chiu, Derek., 黎永釗. January 2001 (has links)
published_or_final_version / abstract / toc / Mechanical Engineering / Doctoral / Doctor of Philosophy
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Effect of submerged vertical structures on ship waves繆泉明, Miao, Quanming. January 2001 (has links)
published_or_final_version / abstract / toc / Mechanical Engineering / Doctoral / Doctor of Philosophy
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Bottom shear stress, wave height and wave set-up under wave transformationNakazaki, Eiji January 1985 (has links)
Typescript. / Thesis (Ph.D.)--University of Hawaii, 1985. / Bibliography: leaves 132-136. / Photocopy. / xxiii, 136 leaves, bound ill. 29 cm
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Interaction of water waves and deformable bodiesBroderick, Laurie L. 25 July 1991 (has links)
A time-domain model was developed to predict the fluid/structure
interaction of a three-dimensional deformable body in a fluid domain subject to
long-crested finite amplitude waves. These nonlinear waves induce transient
motion in the body. In turn, the interaction of the body with the waves modifies
the wave field, causing additional motion in the body. A time-domain simulation
was required to describe these nonlinear motions of the body and the wave field.
An implicit three-dimensional time-domain boundary element model of the fluid
domain was developed and then coupled iteratively with a finite element model of
the deformable body.
Large body hydrodynamics and ideal fluid flow are assumed and the
diffraction/radiation problem solved. Either linear waves or finite amplitude
waves can be treated in the model. Thus the full nonlinear kinematic and dynamic
free surface boundary conditions are solved in an iterative fashion. To implicitly
include time in the governing field equations, Volterra's method was used. The
approach is similar to that of the typical boundary element method for a fluid
domain where the boundary element integral is derived from the governing field
equation. The difference is that in Volterra's method the boundary element
integral is derived from the time derivative of the governing field equation. The
transient membrane motions are treated by discretizing the spatial domain with
curved isoparametric elements. Newton-Raphson iterations are used to account for
the geometric nonlinearities and the equations of motion are solved using an
implicit numerical method.
Examples are included to demonstrate the validity of the boundary element
model of the fluid domain. The conditions in a wave channel were numerically
modeled and compared to sinusoidal waves. The interaction of a submerged rigid
horizontal cylinder with water waves was modeled and results compared to
experimental and numerical results. The capability of the model to predict the
interaction of highly deformable bodies and water waves was tested by comparing
the numerical model to large-scale physical model experiment of a membrane
cylinder placed horizontally in a wave channel. / Graduation date: 1992
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Multi-algorithmic numerical strategies for the solution of shallow water modelsProft, Jennifer Kay 18 May 2011 (has links)
Not available / text
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