Faculty Publications
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Item On numerical modelling of waves, currents and sediment movement around Gurupur-Netravathi river mouth(2010) Radheshyam, B.; Rao, S.; Shirlal, K.G.This paper presents an overview of the investigations that were carried out to understand the coastal process along Bengre and Ullal at the Gurupur-Netravathi River mouth in the west coast of India. This river inlet was facing problems of migration and siltation since several decades and therefore two rubble mound breakwaters were constructed during the year 1994 as an intervention to maintain the inlet mouth. After the construction of these river training jetties, the inlet was stabilized, but severe erosion has been taking place along the Ullal spit on the south side of southern breakwater, since 1996 and heavy accretion on the North of Northern Breakwater along Bengre spit, which is now almost stabilized. This study has been undertaken to understand the hydrodynamics along the beaches adjoining the river mouth. For the present study, various field data was collected for the post monsoon season of 2006. The hydrodynamic (HD), Parabolic mild slope (PMS) and Sediment transport (ST) modules of MIKE-21 software were used to understand the hydrodynamics of the study area. Before the model was made use, it was first validated by using field data to understand the hydrodynamics of the area. Since the field data is of limited duration, data collected from the NMPT wave buoy for an entire year was used for the model simulation. From the studies it was confirmed that current direction and sediment movement follow a similar pattern in monsoon and pre-monsoon and a different pattern during post-monsoon. It is observed that the main cause of erosion is due to direct action of waves on the adjoining beaches of the coast and the beaches in the study area are generally in dynamic equilibrium with a small amount of erosion at Ullal. © 2010 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Assessment of dynamic pressure and wave forces on vertical-caisson type breakwater(Taylor and Francis Ltd., 2022) Kumaran, V.; Rao, M.; Rao, S.The design and construction of coastal structures such as breakwaters, at great water depths is rapidly increasing as a result of the increasing draught of large vessels and off-shore land reclamations. Vertical caisson breakwaters may be the best alternative compared to ordinary rubble mound breakwaters in larger water depths, in terms of performance, total costs, environmental aspects, construction time and maintenance. To fulfilling the functional utility and impact of the structure on the sea environment, it is necessary to study the hydraulic performance. This can be found by field investigation, numerical simulations and by physical modelling. Scale modelling techniques are used to study various coastal engineering problems. This article presents the results obtained by conducting series of experiments in two-dimensional wave flume to assess the hydrodynamic performance of vertical-caisson breakwater, which is made of concrete, with the protection of toe. The dynamic pressure distribution, wave runup, wave reflection, wave forces and stability parameter on the vertical caisson breakwater are discussed. The maximum wave force on the wall breakwater is calculated from measured pressure values and is compared with the forces calculated by Goda’s and Sainflou wave theories. © 2021 Informa UK Limited, trading as Taylor & Francis Group.Item Experimental investigation on L-Oscillating Water Column wave energy converter integrated with floating cylindrical breakwater(Elsevier Ltd, 2025) Harikrishnan, T.A.; Rao, M.; Rao, S.One promising renewable energy source for the future is wave energy, harnessed through L-Oscillating Water Column (L-OWC) Wave Energy Converters (WECs). Combining this device with lightweight floating breakwaters can have several advantages, including absorbing wave energy and attenuating waves. L-OWC and two cylindrical floating breakwaters, one in front of the structure and one at the back are coupled in the current study. Previous research indicates that the L-shaped OWC configuration is highly effective due to its increased added mass and enhanced structural stability. The 1:30 scale model, combining a floating breakwater with an Oscillating Water Column (OWC) system, was experimentally investigated in the wave flume at the NITK, Department of Water Resources and Ocean Engineering. This setup included L-shaped OWCs integrated with cylindrical breakwater configurations (2C, 3C, and 4C). OWCs integrate with lightweight floating breakwaters, offering both wave attenuation and energy extraction. The OWC achieved maximum efficiency of 30% under optimal conditions, with a wave period of approximately 1.8s and a wave height of 0.06 m for the model with three floating breakwaters. The work aligns with the United Nations' Sustainable Development Goals (SDG), specifically addressing clean and affordable energy (SDG 7), industry, innovation, and infrastructure (SDG 9), life below water (SDG 14), and life on land (SDG 15), highlighting its significant impact. © 2024 Elsevier LtdItem Hydrodynamic performance of floating kelp farms: Wave attenuation and coastal protection potential(Elsevier Ltd, 2025) Surakshitha; Rao, M.; Rao, S.Ecologically rich coastal zone play a crucial role in supporting both biodiversity and the economy. “Soft solutions” for coastal protection, such as vegetated breakwaters and artificial reefs, harness natural features to mitigate coastal erosion. Among these, flexible floating vegetation, such as kelp farms, presents a unique mechanism by altering flow patterns differently than bed-fixed vegetation. This study experimentally investigates the effectiveness of floating kelp farms in dissipating wave energy under monochromatic regular waves. The wave heights ranging from 0.06 m to 0.18 m and periods of 1.6 s–2.8 s is considered. The study examines the effects of two non-dimensional parameters: relative farm width (w/L, 0.1 to 2.5) and relative blade length (l/d, 0.25–1.0), representing the ratios of farm width to wavelength and blade length to water depth, respectively. Under the test conditions investigated, the highest wave dissipation coefficient (Kd ? 0.8) is observed for relative blade lengths of 0.75 and 0.5 at a water depth of 0.45 m. The optimal farm configuration occurred at a relative farm width between 0.3 and 0.4. These findings contribute to a better understanding of the role of kelp farm in wave energy dissipation and highlight its potential as a sustainable alternative for coastal protection. © 2025 Elsevier Ltd