Vallam Sundar

Bio: Vallam Sundar is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Wind wave & Shore. The author has an hindex of 24, co-authored 195 publications receiving 1778 citations. Previous affiliations of Vallam Sundar include Indian Institutes of Technology.

Review of the research on emerged and submerged semicircular breakwaters

Abstract: Scientists and researchers are currently focusing considerable attention on the hydrodynamic characteristics of semicircular breakwaters worldwide, particularly in Japan and the People’s Republic o...

Performance of a perforated submerged semicircular breakwater due to non-breaking waves

Abstract: The present experimental research work focused on how a semicircular breakwater performs hydrodynamically under submerged conditions. In the field, a submerged semicircular breakwater may be preferred in front of the vertical breakwater to mitigate the wave forces and to minimize coastal erosion on its lee side. Various parameters affect the hydrodynamic performance of a semicircular breakwater such as the reflection and transmission characteristics, the dimensionless pressures, the horizontal forces and the vertical forces, and these are considered in the present study. Experiments were performed for three different perforations, namely 7%, 11% and 17%, of the exposed surface area with perforations on its sea side (sea-side perforated) and on both sides (fully perforated) owing to regular and random waves. The effect of the water depth was also studied in addition to the effect of perforation. All the hydrodynamic characteristics considered for the present study on the semicircular caisson are presented ...

A new family of generalized distributions

Abstract: 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...

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

Abstract: 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.

Random seas and design of maritime structures

Abstract: 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.

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

Abstract: 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.