Nonlinear Oscillations: Exact Solutions and their Approximations

Kumaraswamy [Generalized probability density-function for double-bounded random-processes, J. Hydrol. 462 (1980), pp. 79–88] introduced a distribution for double-bounded random processes with hydrological applications. For the first time, based on this distribution, we describe a new family of generalized distributions (denoted with the prefix ‘Kw’) to extend the normal, Weibull, gamma, Gumbel, inverse Gaussian distributions, among several well-known distributions. Some special distributions in the new family such as the Kw-normal, Kw-Weibull, Kw-gamma, Kw-Gumbel and Kw-inverse Gaussian distribution are discussed. We express the ordinary moments of any Kw generalized distribution as linear functions of probability weighted moments (PWMs) of the parent distribution. We also obtain the ordinary moments of order statistics as functions of PWMs of the baseline distribution. We use the method of maximum likelihood to fit the distributions in the new class and illustrate the potentiality of the new model with a...

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A new family of generalized distributions

Wind speeds over the world’s oceans have increased over the past two decades, as have wave heights. Studies of climate change typically consider measurements or predictions of temperature over extended periods of time. Climate, however, is much more than temperature. Over the oceans, changes in wind speed and the surface gravity waves generated by such winds play an important role. We used a 23-year database of calibrated and validated satellite altimeter measurements to investigate global changes in oceanic wind speed and wave height over this period. We find a general global trend of increasing values of wind speed and, to a lesser degree, wave height, over this period. The rate of increase is greater for extreme events as compared to the mean condition.

https://researchbank.swinburne.edu.au/file/bca43746-6f16-4ad2-a4b7-27f8d8d60fed/1/PDF (Published version).pdf

Global trends in wind speed and wave height over the past 25 years

Evolution of Design Method Against Random Waves Statistical Properties and Spectral of Sea Waves Transformation and Deformation of Random Sea Waves Design of Breakwaters Design of Coastal Dikes and Seawalls Probabilistic Design of Harbor Facilities Harbor Tranquility and Vessel Mooring Hydraulic Model Tests with Random Waves Theoretical Description of Random Sea Waves Statistical Theory of Irregular Waves Techniques of Random Wave Analysis 2D Computation of Wave Transformation with Random Breaking and Nearshore Currents Statistical Analysis of Extreme Waves Prediction and Control of Beach Deformation Processes.

Random seas and design of maritime structures

The interaction of waves with obstacles is an everyday phenomenon in science and engineering, arising for example in acoustics, electromagnetism, seismology and hydrodynamics. The mathematical theory and technology needed to understand the phenomenon is known as multiple scattering, and this book is the first devoted to the subject. The author covers a variety of techniques, describing first the single-obstacle methods and then extending them to the multiple-obstacle case. A key ingredient in many of these extensions is an appropriate addition theorem: a coherent, thorough exposition of these theorems is given, and computational and numerical issues around them are explored. The application of these methods to different types of problems is also explained; in particular, sound waves, electromagnetic radiation, waves in solids and water waves. A comprehensive bibliography of some 1400 items rounds off the book, which will be an essential reference on the topic for applied mathematicians, physicists and engineers.

Multiple Scattering: Interaction of Time-Harmonic Waves with N Obstacles

Member of JSCE, M. Sc, Dept. of Civil Engineering, Tohoku University (Aobayama, Aoba-ku, Sendai 980-8576, Japan) Member of JSCE, Dr. of Eng., Dept. of Civil Engineering, Tohoku University (Aobayama, Aoba-ku, Sendai 980-8576, Japan) Fellow Member of JSCE, Dr. of Eng., Professor, Dept. of Civil Engineering, Tohoku University (Aobayama, Aoba-ku, Sendai 980-8576, Japan) Dr. of Eng., Professor, Dept. of Ocean Engineering, India Institute of Technology (C-6-13, Second Link Road, IIT Madras, Chennai 600-036, India)

Sensitivity analysis of relationship between tsunami disaster and coastal embankment structure

The semicircular breakwater (SBW) is one of the varieties of breakwaters, which has emerged recently. The world’s first semicircular breakwater has been constructed at Miyazaki port in Japan. The dynamic pressures due to regular waves exerted on a SBW with 7% of its seaside surface area with perforations were measured. The variations of dimensionless pressures for three different water depth (hw ) to total height of the model (ht ), ratios are presented and discussed in this paper. In addition, the reflection and transmission characteristics of the perforated SBW as a function of scattering parameter, ka is reported. The results on the above stated variables for a seaside perforated SBW are compared with the results for an impermeable SBW.Copyright © 2002 by ASME

Hydrodynamic Characteristics of Submerged Impermeable and Seaside Perforated Semicircular Breakwaters

The sloshing of fluid in an enclosed tank due to regular excitation in the horizontal, vertical and rotational modes is investigated through a numerical model. Finite element method with cubic spline and finite difference approximations has been adopted to simulate the fully nonlinear sloshing wave. Herein, the external excitations, including rotational oscillation, are built-in within the kinematic and dynamic free surface boundary conditions. The predictions from the present model are compared with those of Nakayama and Wazhizu due to regular wave excitation in the roll mode, whereas the results from the combined excitations were compared with the results of Chen and Chiang. The sloshing oscillation induced by different combination of tank motions has been subjected to frequency domain analysis. The results exhibited the occurrence of dominant peak at the natural frequencies of the system, irrespective of the excitation frequency for the rotational motion. There is nearly a twofold increase in the peak ...

Numerical simulation of sloshing in a rectangular tank under combined horizontal, vertical and rotational oscillations

A comprehensive experimental work is done to investigate sloshing dynamics in a partially liquid-filled baffled tank, equipped with a floating barge An aspect ratio(hs /l, liquid depth, hs to leng

Performance assessment of porous baffle on liquid sloshing dynamics in a barge carrying liquid tank

To plan for proper mitigation measures, one should have an advanced knowledge of the phenomenon of tsunami propagation from the deep ocean to coastal waters. There are a few methods to predict tsunamis in the ocean waters; one method is the effective use of data buoy measurements. Although data buoys have been used along the Indian waters there has been a tremendous growth in the number of buoy deployment recently. Under the National Data Buoy Programme (NDBP) of India, the 2.2 m diameter discus data buoys were deployed along the east and west coasts of India for measuring meteorological and ocean parameters. It would be advantageous if these buoys could be efficiently used to measure rare events such as tsunamis. Understanding the dynamic behavior of the buoy is of prime importance if a tsunami warning system is to be successful. This may be accomplished through experimental or numerical studies. A comprehensive experimental study has been conducted to understand the dynamic behavior of a wave rider buoy...

Vallam Sundar

Papers

Sensitivity analysis of relationship between tsunami disaster and coastal embankment structure

Hydrodynamic Characteristics of Submerged Impermeable and Seaside Perforated Semicircular Breakwaters

Numerical simulation of sloshing in a rectangular tank under combined horizontal, vertical and rotational oscillations

Performance assessment of porous baffle on liquid sloshing dynamics in a barge carrying liquid tank

Tsunami Wave Interaction with Data Buoys