IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

The time histories of wave elevation and the two horizontal in line and transverse velocity components measured in a groin field were subjected to time domain analysis. The variation of the wave and velocity characteristics with respect to the time of measurement at a particular location and its variation at different locations within the groin field at a particular instant of time are presented and discussed. In addition, the validation of the linear theory in predicting the wave kinematics in the direction of the wave propagation from the measured wave elevations is examined on assumption that wave directional variability is small. -Authors

Department of Ocean Engineering

Journal of Coastal Research

Wave kinematics in a groin field - time domain analysis

Wave records at seven different locations within a groin field have been analysed by both statistical and spectral approaches to study the general wave climate. The wave heights and periods from the wave records were obtained by both upcross and downcross methods for the statistical approach. The variation of different wave height and wave period parameters with respect to the time of measurement at a particular location and its variation at different locations within the groin field at a particular instant of time are presented and discussed in detail in this paper. It is generally found that the wave heights follow the Weibull distribution. © 1992.

Ocean Engineering

Wave climate in a groin field

Monthly visual observations of wave height and wave period available for 1949-1964 were analysed and used to obtain total sediment transport rate. In addition, annual northerly, southerly, gross and net sediment transport rates were computed. About 88% of the gross transport. 1.27 × 106 m3, i.e. a quantity of 1.1 × 106 m3 moves towards north and a quantity of 0.16 × 106 m3 moves towards south. -from Authors

Indian Journal of Marine Sciences

Sediment transport rate and its distribution across surf zone off Gopalpur Port, east coast of India

Wave elevation and the corresponding two horizontal in-line and transverse velocities measured at eight locations in a groin field were analysed. The wave climate and its kinematics are described assuming that the direction variability of waves is negligible. The in-line particle velocity predicted with the measured wave elevation using the linear filter technique iscompared with the measurements. The results of the variation of the average wave and velocity characteristics are presented. © 1992.

Coastal Engineering

Wave kinematics in a groin field-frequency domain analysis

A sediment budget calculation for Paradip port, situated on the east coast of India, is presented, taking into account longshore sand transport and nearshore erosion and deposition. Longshore sand transport rates have been computed using a CERC formula for which the average breaking wave characteristics, obtained from wave refraction diagrams were used. Quantities of nearshore erosion and deposition were obtained from the analysis of near-shore profiles. The study reveals that a quantity of nearly 0·8 million m3 of sand is deposited in the approach channel, while as much as 1·3 million m3 of sand is removed from the northern side of the port annually. It is also clear that the dumping of sand dredged from the port and its approaches beyond the 11 m depth contour on the northern side of the port, does not help to prevent erosion to the north of the port. © 1990.

Ocean and Shoreline Management

Sediment budget for Paradip port, India

The hydrodynamic pressures due to random waves on a large vertical cylinder, resting on a flume bed and piercing above the free surface has been investigated experimentally in constant water depth. The test cylinder was fixed with diaphragm-type pressure transducers at nine different pressure ports with one of them at the still water level (S.W.L.) itself. The cylinder was rotated about its own axis to study the pressure distribution around its circumference. The time histories of the water surface elevation and the corresponding dynamic pressures exerted on the cylinder have been analysed in the frequency domain. The experimental results are compared with the theoretical results based on the linear diffraction theory of MacCamy and Fuchs and the agreement is satisfactory. Finally, the hydrodynamic pressure coefficients obtained from random wave tests are compared with those from regular wave tests. © 1990.

GENERAL

Dynamic pressures on a large vertical cylinder due to random waves

Investigations on the hydrodynamic pressures due to regular and random waves exerted on a large vertical cylinder in a constant water depth are reported in this paper. In the experimental investigation, the test cylinder embedded with diaphragm-type pressure transducers at nine different elevations was rotated about its axis to measure the dynamic pressure around its circumference. The wave field in the neighbourhood of the cylinder was measured at six different locations. The results of the experiments are compared with the linear diffraction theory of MacCamy, R. C. and Fuchs, R. A. [(1954) Wave forces on piles: a diffraction theory. U.S. Army Beach Erosion Board, Technical Memorandum No. 69]. In general, the agreement between the theoretical and experimental results is found to be satisfactory. A comparison between the regular and random wave test results is also presented and discussed. © 1990.

Diffracted wave field and dynamic pressures around a vertical cylinder

Ocean waves and forces induced by them on offshore structures are random in nature. Experience has shown that short term statistics of wave heights can be described by the Rayleigh distribution for narrow band spectra (Longuet-Higgins, 1952) and that the long term statistics or the evaluation of design wave is based on certain well known extreme value distribution such as mixed Frechet distribution (Thom, 1973a, b). This paper presents a new application of the double bounded probability density function to describe the ocean wave statistics. The prime importance is to estimate the most probable maximum wave height for offshore structural designs. © 1989.

Application of double bounded probability density function for analysis of ocean waves

The dynamic pressures around a large diameter vertical cylinder resting on the flume bed and piercing the free surface are measured under regular wave conditions and compared with the results of MacCamy and Fuchs' linear diffraction theory. The linear diffraction theory has been modified to account for the nonlinear effects. The results mostly pertain to deep water conditions with drag effects being negligible and are presented in nondimensional form. The agreement between the theory and experiments are in general found to be good. © 1989 Taylor and Francis Group, LLC.

Journal of Hydraulic Research

Wave induced dynamic pressures on a vertical cylinder in the diffraction regime [Pression dynamiques engendrees par la houle sur un cylindre vertical avec prise en compte de la diffraction]

The experimental investigations on the dynamic pressure distribution around a large vertical cylinder resting on a flume bed and piercing the free surface subjected to regular waves have been carried out in a 4-m wide wave flume in a constant water depth of 2.5 m at Ocean Engineering Centre, Indian Institute of Technology, Madras, India. The cylinder of diameter 400 mm was fixed with diaphragm type pressure transducers at eight different locations below the still water level along with one at the still water level. In addition to this, to study the effect of nonlinearity, one pressure transducer was located above the still water level. The experimental results pertaining to mostly deep water conditions are compared with MacCamy and Fuchs theory and the agreement is found to be good. In order to account for the effects of nonlinearities the above said theory has been modified the results of which are found to be in better agreement. © 1989.

Dynamic pressure distribution on a cylinder due to wave diffraction

The influence of a square base placed at the bottom of a vertical cylinder on the wave induced forces and pressures on the cylinder is reported in this paper. In order to carry out this study, initially, the two dynamic variables on the cylinder in the absence of the base was studied so as to make sure the quality of measurements is satisfactory. The experimental results are compared with MacCamy and Fuchs' theory and the agreement found good. © 1988.

Effect of a base structure on the wave forces and pressures on a vertical cylinder

Hourly wind speed data at Madras Harbour for a five-year period have been analysed. The probability density estimates of hourly and daily mean and maximum wind speeds are presented. The design wind speed for Madras Harbour has been evaluated by three different methods. Mean monthly wind power densities have also been calculated. The average of the hundred-year design wind speed for Madras Harbour obtained through three methods is 88 km h-1. Wind power density is generally low and a maximum value of ∼206 W m-2 is observed during the month of December. © 1988.

Journal of Wind Engineering and Industrial Aerodynamics

Wind climate for Madras Harbour, India

Energy

Wave-power potential off the South-East coast of India

The distribution of longshore current velocities and sediment transport rates across the width of the surf zone off Paradeep Port, India, on the northwest margin of the Bay of Bengal have been evaluated. Monthly distribution of longshore current velocities and associated sediment transport rates are presented. Distribution of sediment transport rates are evaluated up to the breaker zone while those of longshore current velocities extend beyond it. Longshore current velocities are strongest and sediment transport rates are highest in August while weak currents and low transport are observed in October. A comparison of monthly sediment transport rates as obtained by the model of P. D. Komar (1977) and the monthly net sediment transport rates computed using a 1977 US Army Corps of Engineers Coast Engineering Research Center (CERC) formula shows a close correlation between the two values.

Oceans Conference Record (IEEE)

DISTRIBUTION OF LONGSHORE CURRENTS AND SEDIMENT TRANSPORT RATES IN THE SURF ZONE OFF PARADEEP, INDIA.

The seasonal distribution of the longshore current and the seasonal and annual distributions of sediment transport across the surf zone, off the Madras coast, are presented and discussed in this paper. A computer model is developed to evaluate the longshore current - transport distribution across the surf zone. For illustration, a typical bathymetric profile of the Madras coast is selected and the longshore current and sediment transport at different water depths are calculated.

World University root node

Journal of the Institution of Engineers (India): Civil Engineering Division

MODELLING DISTRIBUTION OF LONGSHORE CURRENTS AND SEDIMENT TRANSPORT IN SURF ZONE.

Theoretical and experimental results on wave forces on a bottom seated horizontal cylinder are presented. The influence of wave steepness on in line and transverse forces caused by regular monochromatic waves is discussed. There was good agreement between theoretical and experimental results.

Effect of wave steepness on wave induced forces on large bottom mounted submarine pipelines.

A detailed analysis of visually observed wave data off Madras, South East Coast of India reported for a period of ten years is presented and discussed in this paper. The wave characteristics include wave height, wave period and its direction with respect to North. About five different standard distributions were tried to fit the observed data and found that the wave characteristics off Madras do not follow any of these. The wave power potential off Madras is also discussed. © 1986.

Wave characteristics off the South East Coast of India

Wave attenuation by perforated rigid floating breakwaters was assessed in scale model studies. Earlier analyses of rigid floating breakwater types were also reviewed. Their relative performances are plotted.

IN: THIRD INDIAN CONF. ON OCEAN ENGINEERING, (BOMBAY, INDIA: DEC. 11-13, 1986)

Performance characteristics of rigid floating breakwaters.

The effect of wave steepness on the wave force exerted on an elliptical caisson subjected to regular wave is presented in this paper. Laboratory results are compared with the modified linear diffraction theory proposed by Mogridge and Jamieson (1976). The caisson was tested for angles of orientations of 0°, 30°, 60° and 90° of its major axis with the direction of wave propagation. © 1986.

Studies on the effect of wave steepness on wave force coefficient for elliptical caissons

Wave data gathered by a wave rider buoy off Madras were analysed by both spectral and statistical methods. A computer model, WAVEANAL, was developed to analyse the data, and the spectral density was computed by the covariance method. There was good agreement between results from statistical and spectral analyses. Wave heights followed the Rayleigh distribution.