Faculty Publications
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Item Prediction of damage level of inner conventional rubble mound breakwater of tandem breakwater using swarm intelligence-based neural network (PSO-ANN) approach(Springer Verlag service@springer.de, 2019) Kuntoji, G.; Rao, S.; Rao, M.; Reddy, E.N.B.The conventional rubble mound breakwater is a coastal protective structure commonly used decades before which alone failed to withstand the deepwater wave and its energy, and suffered a catastrophic failure. Keeping in mind both the safe functioning of harbor and stability of the breakwater for the fast-growing economy of the country, different types of breakwaters are being developed to serve this purpose. Tandem breakwater is an innovative type of breakwater, which is a combination of main conventional rubble mound breakwater and submerged reef in front of it. One of the advantages of this breakwater is that most of the wave energy is dissipated and wave intensity is reduced by submerged reef and the smaller waves interact with main breakwater and ensure its stability. Experimental studies are laborious and time-consuming to conduct. Therefore, it is necessary to carry out the detailed study of tandem breakwater stability by making use of simple and alternate techniques using the experimental data. In the present study, an attempt is made to understand the suitability and applicability of PSO-ANN, a hybrid soft computing technique for predicting damage level of conventional rubble mound breakwater of tandem breakwater. Based on the experimental data available in Marine Structure Laboratory, NITK, Surathkal, India, soft computing models are developed. The performances of the models are evaluated using model performance indicators. Results obtained demonstrate that the proposed new approach can be used to predict the damage level of conventional rubble mound breakwater of tandem breakwater efficiently and accurately. © Springer Nature Singapore Pte Ltd. 2019Item A study on shore-line dynamics during and post-construction of breakwaters in kasaragod fishing harbour(Springer Science and Business Media Deutschland GmbH, 2021) Chaitanya, V.K.; Nasar, T.; Paravath, K.Coast belonging to one particular stretch happens to be versatile because of its dynamicity. This dynamicity is accounted because of both natural and man-made activities. Hence, it is necessary to monitor any fragile coastal stretch’s dynamicity in a temporal basis. In this study, an attempt is made to study the dynamicity of coastal morphology using geospatial and numerical approach. Shore-line on both sides of Kasaragod River firth, laterally Karnataka coast of the India, has modified following construction of breakwaters for fishing harbour. The breakwaters were constructed between 2010 and 2015 after which a severe change is observed in shore-line. Construction flaws were reported as a result of which strong waves were formed leading to the difficulty in launching boats into the sea. Coastal morphology needs to be further analysed to propose a more scientific and lasting solution. Shore-line is extracted from field surveyed data (supplied by Department of Harbour Engineering, Kerala). To ensure the forecast end point rate (EPR) and linear regression rate (LRR) for shore-line data, digital shore-line analysis (DSAS) technique was applied and compiled for up to 2017 in response to the construction of a pair of breakwaters at river inlet. © Springer Nature Singapore Pte Ltd 2021.Item Current approaches of artificial intelligence in breakwaters - A review(Techno Press technop2@chollian.net, 2017) Kundapura, S.; Hegde, A.V.A breakwater has always been an ideal option to prevent shoreline erosion due to wave action as well as to maintain the tranquility in the lagoon area. The effects of the impinging wave on the structure could be analyzed and evaluated by several physical and numerical methods. An alternate approach to the numerical methods in the prediction of performance of a breakwater is Artificial Intelligence (AI) tools. In the recent decade many researchers have implemented several Artificial Intelligence (AI) tools in the prediction of performance, stability number and scour of breakwaters. This paper is a comprehensive review which serves as a guide to the current state of the art knowledge in application of soft computing techniques in breakwaters. This study aims to provide a detailed review of different soft computing techniques used in the prediction of performance of different breakwaters considering various combinations of input and response variables. © 2017 Techno-Press, Ltd.Item A laboratory investigation on single row suspended porous pipes was conducted in a two-dimensional regular wave flume to study their hydraulic performance. The effects of porosity, water depth, incident wave steepness and relative wave height on transmission and reflection coefficients were studied. It was found that (a) as incident wave steepness increases transmission coefficient Kt decreases and reflection coefficient Kt increases; (b) water depth has insignificant effect on Kt and Kt for porous pipes; (c) as porosity decreases Kt decreases and Kt increases; and (d) the range of variables studied, as the relative wave height increases Kt increases and Kr decreases.(Performance of single row of suspended porous pipe breakwater) Rao, S.; Rao, N.B.S.; Reddy, Y.V.B.2001Item A laboratory investigation on a single row of suspended porous pipes was conducted in a two-dimensional regular wave flume to study their hydraulic performance. The wave energy losses at the structure were computed and the effects of depth of submergence, incident wave steepness, water depth, pipe diameter, percentage of perforations, size of perforations and relative wave height on loss coefficient were studied. It was found that as incident wave steepness increases, loss coefficient K 1 increases. Water depth has insignificant effect on K 1. It is also observed that as percentage of perforations increases, K 1 increases. For the range of variables studied, as the relative wave height increases, K 1 decreases.(Energy dissipation at single row of suspended perforated pipe breakwaters) Rao, S.; Rao, N.B.S.; Shirlal, K.G.; Guddeti, G.R.2003Item The basic principle involved in the design of S-shaped breakwater is the provision of a wide berm at or around the water level with smaller size armor stones than that used in conventional design, which are allowed to reshape till an equilibrium slope is achieved. An attempt is made to assess the influence of wave height, wave period, and berm width on the stability of S-shaped breakwater with reduced (30% reduction in armor stone weight) armor unit weight. From the investigation, it is found that the berm breakwater with 30% reduced armor weight would be stable for the design wave height if the berm width is 60 cm and wave period 1.2 s. For higher wave periods studied, zero damage wave height reduces by 20-40% of the design wave height. Wave period has large influence on the stability of berm breakwaters. The runup increases with decrease in weight up to Wo/W=0.9. © 2004 Elsevier Ltd. All rights reserved.(Stability of berm breakwater with reduced armor stone weight) Rao, S.; Pramod, Ch.; Balakrishna Rao, K.B.2004Item Stability of breakwater defenced by a seaward submerged reef(2006) Shirlal, K.G.; Rao, S.; Ganesh, V.; Rao, M.The stability of a uniformly sloped conventional rubble mound breakwater defenced by a seaward submerged reef is investigated using physical model studies. Regular waves of wide ranging heights and periods are used. Tests are carried out for different spacings between two rubble mound structures (X/d=2.5-13.33) and for different relative heights (h/d=0.625-0.833) and relative widths (B/d=0.25-1.33) of the reef. It is observed that a reef of width (B/d) of 0.6-0.75 constructed at a seaward distance (X/d) of 6.25-8.33 breaks all the incoming waves and dissipates energy and protects the breakwater optimally. © 2005 Elsevier Ltd. All rights reserved.Item Stability aspects of nonreshaped berm breakwaters with reduced armor weight(2008) Rao, S.; Subrahmanya, K.; Balakrishna Rao, B.K.; Chandramohan, V.R.The present work involves the investigation of the influence of wave height, wave period, water depth, and sea-ward slope on the stability, wave runup, and wave rundown of statically stable rubble-mound berm breakwater. The weight of armor stones used in the present study is 20% lighter than the weight that is required for a conventional breakwater, designed using Hudson formula for a wave height of 0.1 m in the model. In the present work models with a berm width of 0.6 m, at constant depth of 0.32 m from the seabed were tested. The damage to the breakwater model with the berm was compared with the results on a model without the berm using different armor weights. The variation of relative runup and rundown was found for different values of wave steepness and water depths in front of the structure. The damage to the breakwater, wave runup, and rundown for the structure with seaward slope 1:2 and 1:1.5 were compared. The investigation was carried out in the Marine Structures Laboratory, Department of Applied Mechanics and Hydraulics, National Institute of Technology Karnataka, Surathkal. © 2008 ASCE.