Faculty Publications
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Item Numerical investigation of Edinburgh Duck wave energy converter integrated with floating breakwaters(Springer Nature, 2023) Vidyabhushan, R.R.; Karmakar, D.Hydrodynamic performance of hybrid floating structures consisting of Edinburgh Duck Wave Energy Converter (ED-WEC) integrated to different shapes of Floating Breakwaters (FBW) namely (i) box-type FBW, (ii) trapezoidal-type FBW, (iii) π -type FBW, (iv) parabolic-type FBW and (v) semi-circular-type FBW are investigated based on small amplitude wave theory. The study is performed on the harvesting of wave energy and increasing the wave power absorption from the scattered and the reflected waves due to the presence of oceanic structures integrated with WEC. The hydrodynamic analysis for the hybrid floating breakwater-WEC system is analysed using Ansys AQWA. The associated diffractions and motions of the hybrid floating breakwater-WEC system are examined. The motion responses and resulting wave forces for the heave motion of ED-WEC with different parameters such as width of ED, draft of ED, distance between ED-WEC and floating breakwater and angle of incident are investigated. Further, the study is carried out for isolated ED-WEC and isolated breakwaters. The study performed will help in developing an efficient and reliable form of device for harnessing maximum wave energy into electricity along with the breakwater having practical application of ED-WEC at the initial stages of design. The study will provide a potential solution of generating power from the wave energy and as a coastal defence structure with the presence of floating breakwaters. © 2023, The Author(s), under exclusive licence to Sociedade Brasileira de Engenharia Naval.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 Hydrodynamic performance of H-shaped floating breakwater in the presence of a partially reflecting seawall(Taylor and Francis Ltd., 2025) Panda, A.; Muduli, R.; Karmakar, D.; Rao, M.The present study examines the hydrodynamic interaction of surface gravity waves with freely floating H-shaped porous structure situated close to a partially reflecting seawall and without seawall using Multi-Domain Boundary Element Method (MDBEM). The study is performed to examine the performance of the H-shaped floating breakwater for sway, heave, and roll motion, as well as the effects of a seawall on the hydrodynamic parameters associated with the floating body. The horizontal wave force, added mass, radiation damping coefficients, and the horizontal, vertical, and moment acting on the floating structure are analysed under different structural configurations. The numerical model developed using MDBEM approach is validated using the results available in the literature. The primary findings demonstrate that reducing the structural moments and added mass and wave force coefficients, and constructing a seawall adjacent to the breakwater, greatly enhances performance in deep water. The reflection coefficient by the seawall greatly impact damping in shallow water depth but have minimal effect in deep water region, indicating that water depth significantly impacts the wave transformation. The present study provides important insights for developing marine infrastructure in various coastal and offshore environments by demonstrating the potential for customised engineering solutions to reduce wave impacts successfully. © 2025 Informa UK Limited, trading as Taylor & Francis Group.Item Hydrodynamic performance of hybrid floating breakwater integrated with oscillating water column(SAGE Publications Ltd, 2025) Vishwakarma, R.D.; Karmakar, D.The present study investigates the hydrodynamic performance of different types of hybrid floating breakwaters (HFB) integrated with an oscillating water column (OWC). The study is performed for five different cross-sectional shapes of HFB, such as rectangular, box, H, ?, and trapezoidal, with the inclusion of OWC of the same dimension in all of the hybrid floating breakwaters. The performance of the HFBs is examined for its motion response, wave transmission coefficient, and power capture under the action of the regular waves, considering the incident wave normal to the structure. The motion response and wave transmission characteristics assessment are based on potential flow theory, and the power capture due to the HFB is assessed using the volume of fluid (VOF) flow computation method. The HFB model performing better in terms of transmission coefficient and power capture considering wider bandwidth for the considered surface gravity wave frequencies is selected to investigate the effect of changes in HFB’s parameters, such as length, width, draft, and wave incident angle on the hydrodynamic performance. Additionally, the streamline contours for the air flow velocity variation through the OWC chamber in different types of hybrid floating structures are analysed for better understanding of flow through visualisation. The aforementioned streamline contour is determined for the wave frequency where the maximum wave energy capture in the HFB models is observed. The study will facilitate the researchers to comprehensively investigate the stability of hybrid floating breakwater under the influence of regular waves with the help of the findings of the present investigation. © IMechE 2025Item 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 Hydroelastic analysis of VLFS integrated with porous floating box breakwater using multi-domain boundary element method(Elsevier Ltd, 2025) Hemanth, S.; Karmakar, D.The present study analyses the feasibility of integrating a Very Large Floating Structure (VLFS) with a porous floating box-type breakwater kept fixed in its position to analyze the hydroelastic responses within the integrated system based on linearized wave theory. The integrated VLFS-breakwater system, comprising the VLFS and the porous box-type breakwater assures in mitigating the structural effects induced by waves. The coupled Multi-Domain Boundary Element Method (MDBEM) and Finite Difference Method (FDM) are employed to investigate the performance of integrated VLFS-breakwater system. The computational framework employs the MDBEM to model the fluid domain and the floating breakwaters, while the VLFS is modeled using the FDM approach. The study considers three distinct relative positions of the VLFS integrated with a floating breakwater on (i) the leeside, (ii) the seaside, and (iii) on both leeside and seaside of the VLFS. The numerical study is performed based on thin-plate theory and small amplitude wave theory. The study corroborates its numerical findings with existing literature, supporting the validity of its methodology. The integrated system effectively reduces forces acting on the VLFS by absorbing the primary impact of waves. Consequently, the hydroelastic response of the VLFS is reduced, preserving its structural integrity and enhancing overall safety. The study signifies the importance of integrating the porous box-type breakwater with the VLFS. The importance of the orientation of the structure towards the sea waves, the porosity of the breakwater, the effect of relative spacing between the breakwater and VLFS and variations in hydrodynamic responses with respect to the placement of the floating breakwater are thoroughly discussed. The study performed will be helpful in the design and implementation of integrated VLFS-breakwater system, enhancing their robustness and safety in maritime environments. © 2024 Elsevier LtdItem Hydrodynamic analysis of arrays of integrated U-shaped OWC device and ?-breakwater(Elsevier Ltd, 2025) Muduli, R.; Karmakar, D.The hydrodynamic performance of arrays of hybrid floating breakwater consisting of pile-restrained U-shaped Oscillating Water Column (U-OWC) integrated with ?-breakwater is analysed using Boundary Element Method (BEM). The study is performed to analyse the theoretical maximum efficiency, reflection and transmission coefficients and horizontal wave force coefficient on the top wall of the U-OWC integrated with breakwater as a function of the incidence angle as well as the non-dimensional spacing between the devices. The geometrical variations of the U-OWC relative chamber width and draft are considered to study the effect on the hydrodynamic performance. The study reveals that on increasing the relative draft of the U-OWC, the energy conversion efficiency is improved whereas the increase in the relative chamber width beyond 0.5 times the water depth (A2/h=0.5) was detrimental to the efficiency. Further, the wave reflection coefficient as a function of incidence angle is noted to be unaffected by geometric variations of the U-OWC. The wave force coefficients as a function of the non-dimensional spacing is observed to exhibit a sinusoidal pattern for the wave interaction with array of integrated U-OWC with breakwater. The numerical investigation on the array of integrated devices will enhance the knowledge and determine the performance of the array of integrated device. © 2025 Elsevier LtdItem Hydrodynamic performance of a hybrid floating breakwater-wave energy conversion system(SAGE Publications Ltd, 2025) Patil, S.B.; Karmakar, D.The study presents the hydrodynamic performance and wave energy conversion of a hybrid floating breakwater under the framework of small amplitude linear wave theory. The hybrid floating breakwater is composed of a partially liquid-filled rectangular-box type tank with built-in buoys connected to a Power Take-Off (PTO) (linear inductance generator) and is excited under regular wave conditions for (a) constrained roll motion, and (b) constrained surge, heave, and roll motion. The Boundary Element Method (BEM) is employed with the assumption of modest sloshing in the tank of the hybrid floating breakwater to estimate the hydrodynamic efficiency of the hybrid floating breakwater. Further, the experimental investigation on the Wave Energy Converter (WEC) capabilities and the hydrodynamic coefficients (wave reflection and transmission coefficients) are estimated for the excitation frequencies corresponding to nondimensional wavenumber. The present study reveals that the hybrid concept improves wave attenuation performance by 20%–35% compared to conventional floating breakwaters by increasing wave attenuation, damping and stabilizing the wave transmission coefficient (Formula presented) within (Formula presented). The experimental investigation shows that hybrid floating breakwater attaints its floating stability for the depth 15 – 25% of partially filled fluid for which the proposed design as floating breakwater as well as WEC system is achieved for a wide range of excitation frequencies. Furthermore, the hybrid floating breakwater functions as a barrier which is noted to be capable of significantly attenuating incoming progressive waves below the predetermined threshold values of wave attenuation characteristics, in addition to converting wave energy. © IMechE 2025. This article is distributed under the terms of the Creative Commons Attribution 4.0 License (https://creativecommons.org/licenses/by/4.0/) which permits any use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access page (https://us.sagepub.com/en-us/nam/open-access-at-sage).Item Hydrodynamic analysis of U-shaped OWC with varying bottom profiles integrated with ?-breakwater(SAGE Publications Ltd, 2025) Muduli, R.; Karmakar, D.In the present study, the fixed U-OWC integrated with ?-shaped breakwater is analysed considering three different bottom profiles (straight, inclined, and curved) of the interior chamber of the U-OWC. The hydrodynamic performance is assessed based on the theoretical maximum efficiency, radiation susceptance and conductance, reflection, transmission and dissipation coefficients and force coefficient on the top lip wall of U-OWC and front face of breakwater. The influence of geometric variations such as width of U-channel, draft of U-OWC, draft and width of breakwater and distance between the two structures on the hydrodynamic performance is analysed using Boundary Element Method (BEM). The study depicts that the presence of a wider U-channel width impairs the energy conversion efficiency of the U-OWC and increasing the draft of the U-OWC improves the efficiency of the device. Further, changing the bottom profile of the internal chamber of U-OWC changes the natural frequency of the device without hampering the efficiency. In addition, as the distance between the two structures is increased, transmission of waves decreases. The influence of wave force on the breakwater is noted to be maximum when the leading U-OWC structure has a curved bottom. The study on the variation of the bottom profile of the fixed U-OWC integrated with breakwater will be helpful in the design and analysis of efficient hybrid floating breakwater system. © IMechE 2024. This article is distributed under the terms of the Creative Commons Attribution 4.0 License (https://creativecommons.org/licenses/by/4.0/) which permits any use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access page (https://us.sagepub.com/en-us/nam/open-access-at-sage).Item Influence of seabed topography on hydroelastic behavior of VLFS integrated with porous breakwater(Elsevier Ltd, 2025) Hemanth, S.; Karmakar, D.The present study investigates the effect of seabed topography on the hydroelastic behaviour of a Very Large Floating Structure (VLFS) integrated with porous floating breakwaters for inclined, irregular, stepped and irregular stepped seabed conditions. The real-world marine environments feature complex topographies that significantly influence wave-structure interactions. The integrated system combines a flexible VLFS with porous floating breakwaters designed to attenuate wave energy and mitigate structural responses. A coupled Multi-Domain Boundary Element Method (MDBEM) for fluid dynamics and the Finite Difference Method (FDM) for structural analysis is employed for the computation, allowing for accurate modelling of wave-structure-seabed interactions. The numerical model developed for the MDBEM-FDM approach is validated against established benchmark results available in the literature. The key parameters, such as seabed slope, seabed irregularity, breakwater porosity, and placement, are analysed to evaluate their impact on hydrodynamic forces, bending moments, and strain distributions. The numerical results indicate that irregular seabed can amplify localized bending stresses by up to 30 % compared to flat beds, while inclined seabed alters wave reflection patterns, intensifying asymmetric loads. However, porous breakwaters effectively reduce transmitted wave energy by 40–50 %, suppressing adverse hydroelastic responses. The study emphasizes the importance of considering seabed topography while designing VLFSs integrated breakwater. The presence of the breakwater helps in the reduction of the stresses brought on by uneven seabed conditions by strategically placing them and optimizing their porosity. The findings from the present study can contribute to the development of resilient VLFS systems in real-world marine environments, ensuring structural integrity under varying seabed conditions. © 2025 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.