Showing papers by "Vallam Sundar published in 2014"

Shoreline changes along the Northern coast of Chennai port, from field measurements

Abstract: Shoreline movement is a complex phenomenon that is the result of both natural processes and man-made effects. Some of these processes occur over millennia; others are recent and may be cyclic. Understanding changes to the shore requires both a complete understanding of the underlying processes and an ability to accurately measure the changes. This paper presents the one-line shift method of determining datum-based shoreline positions for every month using Arc-GIS and sectional changes using data field measured data with the help of real-time kinematic GPS (RTK-GPS). This result shows the erosion and accretion patches and its volume for the study area.

Sensitivity analysis of relationship between tsunami disaster and coastal embankment structure

Abstract: 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)

Inter comparison of wave height observations from buoy and altimeter with numerical prediction

Abstract: An inter-comparison exercise has been carried out between altimeter derived significant wave height with buoy measurements and numerical prediction. Measurements during the year 2004 have been taken from the buoys located in the Arabian Sea and Bay of Bengal. The statistics of variation between these observations has been studied at each buoy locations with the special emphasis to explore the applicability of altimeter measurements and numerical model prediction.

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

Abstract: 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.

Asymptotic Analysis of Sloshing in a Rectangular Tank

Abstract: An Asymptotic solution of liquid sloshing motion in a rectangular tank is presented based on the potential flow theory. A rectangular tank is excited harmonically, in the sway and heave modes. The Stokes perturbation theory is used to resolve the boundary value problem. The perturbed problem reduces to the non-homogeneous Mathieu's equation in the case of coupled harmonic excitations, which induces the sloshing motion subjected to parametric rolling of the tank. Lindstedt-Poincare' method is used to determine the stable solution of the Mathieu's equation.

Comparative evaluation of erosion accretion criteria for a tropical beach

Abstract: Beach processes along the NeendakaraKayamkulam sector on the coast of Kerala related to the offshore waves and local wind conditions are investigated. This study is based on the field observations made during March 2012 to March 2013, which indicates that a major portion of the beach is dynamically stable except for a few hot spot locations,wherein, the natural balance or equilibrium has been disturbed due to excessive mining or introduction of hard structures as a part of harbour development activities or shore protection measures. It is also observed that the condition of some of the areas which were under heavy erosion during the last decade has improved considerably or remained more or less stable in recent past probably due to the protection measures adopted.

A Load Cell for the Measurement of Slack Mooring Forces

Abstract: A load cell for the measurement of mooring forces is designed using the load-strain principles and the same is verified for its efficiency by structural modeling. A model load cell is fabricated and calibrated through laboratory experiments using three axes loading as well as mooring chain catenary principles. Experiments are also conducted in the physical wave tank to measure the mooring forces exerted on a disc shaped data buoy by using the designed load cell. The details of the design concepts, structural modeling, instrumentation, calibration, wave tank experiments and the results are discussed in this paper.