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

The response characteristics of a discus data buoy under the action of nonlinear waves are investigated through an experimental set-up in a wave tank. The details of the model, instrumentation, tes...

Response characteristics of a discus shaped data buoy in nonlinear waves

The reduction of the greenhouse gas emission generated through the usage of fossil fuel has become quite vital forcing us to look for alternative renewable energy sources. Among the renewable energy sources, ocean wave energy looks promising leading to worldwide involvement of researchers in the refinements of a number of the concepts. The conversion of energy available in ocean waves requires an interface device to interact with the kinetic and kinematic phenomena under the waves. These devices are known as wave energy converters (WECS). Among the available WECS oscillating water column (OWC) stands out as one of most promising concept. Though the OWC concept has emerged from laboratory model type to prototype plant, the high cost of production makes it less attractive in commercialism. This necessitates further refinement in the configuration of OWC concept to make it more attractive leading to economically competent. This can be achieved either by improving the efficiency or by integrating it with coastal protective breakwaters, viz., offshore detached breakwaters. The double chamber oscillating water is an innovative concept which can bring forth both efficiency and additional stability once it becomes an integral part of coastal breakwater. This system captures the high magnitude of dynamic pressure as the excitation force for the oscillation inside the OWC. The trajectory of flow pattern can provide additional vertical load which will enhance the stability factor of the breakwater. In this paper the wave power absorption capacity of a 1:20 scale physical model under varying regular wave characteristics is reported. In this insightful study the objective assessment over the hydrodynamic performance reveals the parametric influence over wave power absorption capacity of the device.

Vallam Sundar

Papers

Response characteristics of a discus shaped data buoy in nonlinear waves

Wave Power Absorption Capability of a Multi-Resonant Double Chamber Oscillating Water Column Device

Studies on wave-subsea pipeline interaction

Liquid Sloshing Dynamics in a Container Subjected to Coupled Mode Excitation

Hydrodynamic characteristics of curved front face pile-supported breakwaters in random waves