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...

/pdf/a-new-family-of-generalized-distributions-1jh9brns7x.pdf

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

Experimental Investigations on Wave Transmission at Submerged Breakwater with Smooth and Stepped Slopes

Vortex-induced vibrations of elastically mounted circular cylinder at Re of the O(105)

An experimental study has been carried out to measure the pressures on the walls and on the top cover plate of a tank that is partially filled with liquid and rigidly mounted in a barge. Herein, the barge has been subjected to the combined degrees of excitation, namely, sway, heave and roll. Four liquid fill levels with aspect ratio (h s /l, where h s is the static liquid depth and l is the tank length) of 0.163, 0.325 (nearly critical depth), 0.488 and 0.585 are considered for the studies. The effects of wave excitation frequencies and amplitudes on the pressure variation have been studied in detail and, the salient results are herein reported.

Sloshing pressure variation in a barge carrying tank

Offshore and coastal structures experience wave impact loads particularly due to breaking waves throughout its design period. In the present paper, an experimental program has been devised to improve our perceptive of the physics and the characteristics of impact pressures due to breaking waves on a vertical wall. The salient features of the study such as model details, breaking wave simulation, the impact and dynamic pressure variation along the depth of the wall are presented. The maximum impact pressure magnitude is found to be of the order of ten times that of the non-breaking dynamic pressure and it always occurred above the still water level for different intensities of breaking waves considered. The minimum pressure rise time is observed to be 0.235 ms.

https://journals.sagepub.com/doi/pdf/10.1260/1759-3131.1.3-4.155

Breaking Wave Impact Pressure on a Vertical Wall

The principle of oscillating water column within a chamber due to the propagating oscillatory ocean waves being converted into clean energy through wave energy convertor referred to as Oscillating water column (OWC) device is a well proven concept that still remains as one of the most promising alternate sources of energy from the Ocean. The OWC has single column of water oscillation, whereas, Double Chamber Oscillating Water Column (DCOWC) has two chambers of water oscillation. DCOWC is relatively a new concept. In this paper, the performance characteristics of a DCOWC is evaluated through a well-controlled experimental investigation in a wave flume. The conceptual design aspect of DCOWC and its uniqueness compared with the present state of art in wave energy converters (WECs) are explained. The efficiency of the system is assessed by considering the variations in the geometrical dimensions of the system along with the different characteristics of incident waves. The methodology adopted for evaluating th...

https://journals.sagepub.com/doi/pdf/10.1260/1759-3131.4.1.21

Vallam Sundar

Papers

Experimental Investigations on Wave Transmission at Submerged Breakwater with Smooth and Stepped Slopes

Vortex-induced vibrations of elastically mounted circular cylinder at Re of the O(105)

Sloshing pressure variation in a barge carrying tank

Breaking Wave Impact Pressure on a Vertical Wall

Wave Interaction with a Double Chamber Oscillating Water Column Device