Faculty Publications
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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 Hydrodynamic analysis of an H-shaped pile-restrained floating breakwater combined with a pair of vertical barriers(Elsevier Ltd, 2024) Panda, A.; Karmakar, D.; Rao, M.The present study analyses the performance of a composite breakwater consisting of an H-shaped breakwater attached with vertical/inclined barriers held from both sides using the Multi-Domain Boundary Element Method (MDBEM). The study is performed to analyse the wave transformation characteristics (reflection and transmission), wave energy dissipation and horizontal wave forces due to the gravity wave-structure interaction. The hydrodynamic performance of the integrated breakwater is performed due to the effect of changing various structural properties such as porosity, width and depth of structural elements, relative spacing between breakwater and barrier, angle of incidence and the inclination of the barriers. The boundary conditions and the corresponding edge conditions are incorporated for each surface and interface and correlated with Green's function to solve the boundary value problem. The detailed study proposes the suitable dimensions of the structural elements of the breakwater for optimal performance. The application of inclined barriers over the vertical barrier in certain conditions for maximising wave reflection is presented and analysed to understand the effectiveness of the barrier inclination. The favourable barrier dimensions and the suitable relative spacing for deep water regions are discussed, and the effect of rigidity and porosity of the barriers are analysed to maximise breakwater performance in wave attenuation. On considering the suitable design parameters and structural stability, the composition of vertical/inclined barriers with an H-shaped pile-restrained floating breakwater serves as a protective component by encountering maximum wave force and dissipating considerable wave energy to provide an efficient solution in harbour protection. © 2024 Elsevier LtdItem 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 Effect of seabed condition on the hydrodynamic performance of a pile-restrained H-shaped floating breakwater(Taylor and Francis Ltd., 2025) Panda, A.; Karmakar, D.; Rao, M.The present study investigates the hydrodynamic analysis of pile-restrained H-shaped porous breakwater for various seabed conditions using the small amplitude wave theory. The Multi-Domain Boundary Element Method (MDBEM) is employed to investigate the influence of parametric variations on the hydrodynamic coefficients and horizontal wave force under normal and oblique incident waves. The numerical accuracy is ensured by comparing it with the available literature. The numerical investigation on the hydrodynamic performance of the H-shaped breakwater is performed for various seabed configurations considering different angles of slope, the width of slope/step/obstacle, step height, number of steps, soil permeability, angle of wave incidence, the width of flange and submergence draft of the web of the H-shaped structure. The findings indicate that the seabed undulation has a higher wave impact on the breakwater than the horizontal seabed. In addition, the study suggests that the sloped seabed is preferable in deeper water depths to reflect waves efficiently and the seabed permeability can affect the hydrodynamic coefficients in shallow and intermediate water depths. The study performed on the H-shaped breakwater for varying seabed topography will be helpful in the design and construction of a suitable H-shaped breakwater for an effective wave absorber in coastal regions. © 2025 Informa UK Limited, trading as Taylor & Francis Group.Item 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 LtdItem Hydrodynamic performances of vertical wall type breakwater with slotted barriers: a physical and numerical approach(Nature Research, 2025) Kumaran, V.; Venkateswarlu, V.; Rao, M.The present experimental investigation examines the surface gravity wave reflection and fluid force experienced by the vertical wall-type breakwater against the dimensionless water depth. The toe protection is provided and experimentally analyzed to secure the vertical caisson breakwater from the failures. Two types of barriers such as vertical slotted barrier (VSB), and horizontal slotted barrier (HSB) are installed and away from the vertical caisson breakwater to create a wave trapping chamber. The effect of barrier porosity varying from 10 to 50% on wave trapping and the scattering coefficients, i.e., pressure distribution, wave force, wave reflection, and wave runup, is reported. The integrity of the present study’s experimental results is ratified with the numerical results, and a decent correlation is observed between both results. In addition, the wave dissipation and flow field analysis near the vertical barrier are also shown using the numerical simulations. The experiments show that the wave reflection reduces with an increase in the dimensional water depth, and the pressure force on the vertical caisson breakwater increases with an increase in the barrier porosity. The performance of the horizontal slotted barrier is significant compared with the vertical slotted barrier in that it effectively distributes the incident wave into seaside wave energy and trapped wave energy. The study strongly believes that the pressure force is a trivariate function, i.e., wave height, barrier porosity, and free spacing available between the barrier and wall. The moderate barrier porosity and the higher free spacing help reduce the fluid force experienced by the vertical caisson breakwater. © The Author(s) 2025.