Faculty Publications
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Item Performance evaluation of submerged breakwater using Multi-Domain Boundary Element Method(Elsevier Ltd, 2021) Patil, S.B.; Karmakar, D.The gravity wave interaction with submerged breakwater of different structural configurations are investigated based on the small-amplitude wave theory. The boundary value problem is analysed in two-dimension using the linearized wave theory in water of finite depth. The submerged breakwater structural configuration such as (i) thin-walled type (impermeable), (ii) rectangular type (impermeable and permeable), (iii) triangular type (impermeable, permeable, perforated), (iv) trapezoidal type (impermeable, permeable, perforated) and (v) Tandem type (impermeable, permeable, perforated) are considered to analyse and performance of the breakwater. The numerical model is developed using the Multi-Domain Boundary Element Method (MDBEM) to analyse the hydrodynamic scattering coefficient (such as reflection, transmission and dissipation coefficient) for the change of physical parameters such as relative spacing between the breakwaters, relative water depth and structural dimensions. The convergence of the present numerical model is performed for the specific case of tandem breakwater and numerical computation is validated with the results available in the literature. The wave reflection and transmission coefficient along with wave force on the structure is analysed for different shapes, structural parameters and geometrical parameters of the breakwater to maximize the efficiency of breakwater. In the case of permeable breakwater, the submerged tandem breakwater is found to be more efficient in wave transformation as compared to rectangular, triangular and trapezoidal permeable submerged breakwaters. The comparative analysis performed on different configurations of the breakwater in the present study will be helpful in the effective design of the breakwater near the harbour regions. © 2021 Elsevier LtdItem Oblique wave interaction with a two-layer pile-rock breakwater placed on elevated bottom(Taylor and Francis Ltd., 2022) Venkateswarlu, V.; Praveen, K.M.; Vijay, K.G.; Anil, K.; Karmakar, D.The two-layer pile-rock porous breakwater consisting of the upper porous layer, middle porous layer placed over the bottom rigid layer (elevated bottom) is proposed as an active wave absorber for significant wave damping and wave trapping. The two-layer rock core is placed between the two thin porous barriers (piles), and the thin barriers/ piles are useful to reduce the wave force experienced by active two-layered breakwater. The eigenfunction expansion method is used to analyse the physical problem on considering the continuity in fluid velocity and pressure along with mode-coupling relation based on classical linearised potential flow theory. The developed analytical model is validated with the available results and then various hydrodynamic characteristics such as wave reflection, transmission, damping, wave forces on seaward, leeward barriers and wave force experienced by the vertical cliff are presented. The porosity of surface layer shows an effective role in reducing the harmonic oscillatory pattern in the hydrodynamic quantities, and the study suggests the higher surface layer porosity (Formula presented.) as compared with bottom layer porosity for optimal wave damping. © 2021 Informa UK Limited, trading as Taylor & Francis Group.Item Hydrodynamic Performance of Fixed Floating Structures Coupled with Submerged Breakwaters Using the Multidomain Boundary Element Method(American Society of Civil Engineers (ASCE), 2023) Patil, S.B.; Karmakar, D.The hydrodynamic characteristics of fixed floating structure (FFSs) of various configurations, such as rectangular fixed floating structures and trapezoidal fixed floating structures coupled with submerged breakwaters of two different shapes, namely, rectangular breakwater and trapezoidal breakwater, are investigated using the multidomain boundary element method under the framework of small-amplitude wave theory. The hydrodynamic analysis of the FFS with and without the presence of submerged breakwater is performed for the variation in physical parameters such as a change in structural parameters of the submerged breakwater (shape, relative submergence depth, relative crest width, and structural porosity), structural parameters of FFS (shape and structural width), wave parameter (angle of incidence), and relative spacing between the FFS and submerged breakwater. The study demonstrates, for a given range of incident wave angles, periodic values of the distance between the submerged breakwater and the FFS and optimal shape combinations for which the coupled structures act effectively in attenuating wave force acting on the FFS and optimizing wave transformations. In addition, to enhance the hydrodynamic performance, the presence of reef structures in front of the FFS is associated, which results in Bragg's resonance with a phase shift in peaks of wave reflection and transmission coefficient caused by changing the structural porosity of the submerged breakwater, indicating that the proposed models are more flexible, allowing demand-based control over shore dynamics and coastal management. The study will be useful for coastal management and safeguarding floating structures by selecting various forms and combinations of coupled FFSs with submerged porous breakwaters. © 2023 American Society of Civil Engineers.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 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 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 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.