Faculty Publications
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Item A novel single source multilevel inverter with hybrid switching technique(John Wiley and Sons Ltd, 2022) Nageswar Rao, B.; Yellasiri, Y.; Shiva Naik, B.; Venkataramanaiah, J.; Aditya, K.; Panda, A.A novel multilevel inverter (MLI) configuration with the hybrid switching technique is presented in this paper. The proposed MLI consists of the H-bridge combination with unidirectional switches, half-bridges, and transformers. The suggested MLI with the additional cascaded connection increases to higher voltage levels. The number of employed components in this topology is drastically minimized. Therefore, the complexity, cost, and volume of the proposed topology are also reduced. The operation of the suggested topology is tested through the improved novel switching technique. This modulation method reduces the total harmonic distortion (THD) and produces high root mean square (RMS) voltage. Further, a comprehensive comparison with the recent MLI topologies is performed to validate the merits of the suggested inverter. Simulation and experimental results verify the suggested topology performance using the new modulation technique at different loading conditions and modulation indices. © 2021 John Wiley & Sons, Ltd.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 Oblique wave interaction with pile-restrained dual H-shaped breakwater(National Institute of Science Communication and Policy Research, 2024) Panda, A.; Karmakar, D.; Rao, M.The hydrodynamic performance of pile-restrained dual H-shaped floating breakwater is investigated using the small amplitude wave theory considering oblique wave incidence. The research on a single H-shaped floating structure supported by the piles has demonstrated effective wave reflection and wave trapping due to its distinctive configuration, composed of a vertical member called a web and a horizontal member called a flange. Thus, the dual H-shaped breakwater is proposed to enhance the breakwater’s efficiency and to provide additional support to the leeside structure. The present analysis is performed by varying the structural parameters such as the width and submergence draft of the web, flange width of the dual H-shaped breakwaters and the corresponding effect on the hydrodynamic coefficients along with the wave-induced force acting horizontally on the breakwater using Multi-Domain Boundary Element Method (MDBEM). Based on the study, the leeside structure experiences a greater wave force than the primary H-shaped structure placed seaside for the critical angle of incidence. The dual H-shaped breakwater is noted as a highly effective harbour defence solution based on the structural and design specifications. The dual H-shaped pile-restrained floating breakwaters provide protection by absorbing the highest wave force and releasing a significant quantity of wave energy. © 2024, National Institute of Science Communication and Policy Research. All rights reserved.Item Hydrodynamic Performance of H-shaped Pile-restrained Floating Breakwater Integrated with Horizontal Plates(Editorial Board of Journal of Harbin Engineering, 2024) Panda, A.; Karmakar, D.; Rao, M.This study analyzes the hydrodynamic performance of an H-shaped pile-restrained composite breakwater integrated with a pair of horizontal plates placed on the seaside and the leeside of the breakwater. The wave interaction with the H-shaped breakwater is examined by analyzing the wave reflection, transmission, and dissipation coefficients. Additionally, the horizontal wave force coefficients are evaluated to analyze the effectiveness of the horizontal plates when integrated with the main structure. The primary structural parameters directly affect the performance of the composite breakwater and are varied within the feasible range of nondimensional wave numbers, relative spacings, and incident wave angles. This study presents a comparative analysis of the arrangement of the horizontal plates in terms of spacing and inclinations inward and outward to the breakwater using a multidomain boundary element method (BEM). The variation of the structural parameters proposes suitable dimensions for integrated H-shaped breakwater with horizontal plates that provide optimal performance in shallow and deep-water regions. The optimum plate porosity, dimensions of the H-shaped structure, inclinations, and spacing between the plate and breakwater are thoroughly discussed. This study shows that impermeable plates are the excellent means to control the wave force in the intermediate water depth regions than in deep-water regions at resisting wave force. The wave force coefficient on the breakwater is significantly larger than that on the seaside plates. Interestingly, inward-inclined plates perform most efficiently at angles greater than 5°, except in deep-water regions where horizontal plates perform better. In addition, this study noted that regardless of water depth, the outward-inclined plates are the least effective in reflecting the incident wave energy. This study will help plan the layout of suitable composite structures for efficient near-shore and offshore harbor protection according to the site criteria and environmental conditions. © Harbin Engineering University and Springer-Verlag GmbH Germany, part of Springer Nature 2024.Item Performance Evaluation of Pile-Restrained Floating Breakwater using the Multi-domain Boundary Element Method(Editorial Board of Journal of Harbin Engineering, 2025) Panda, A.; Karmakar, D.; Rao, M.This study investigates wave interactions with different configurations of pile-restrained floating breakwater (T-shaped, ?-shaped, ?-shaped, H-shaped, I-shaped, and rectangular) with the multi-domain boundary element method. The analysis incorporates horizontal and vertical stratification in floating structures. Key scattering factors, including reflection, transmission, and dissipation coefficients, are evaluated to determine the influences of the structural and geometric parameters on floating breakwater performance. Additionally, this study examines the horizontal wave forces exerted on the seaward and leeward sides of the structures. Model convergence is validated, and the accuracy of the computational results is confirmed by comparing the wave reflection and transmission coefficient for rectangular floating pontoon and stratified submerged porous box. Further validation is provided by comparing the numerical results for an H-shaped model with experimental data obtained from wave flume testing. Findings indicate that the H-type breakwater demonstrates superior performance in deep-water environments, whereas the ?-type structure exhibits greater wave energy transmission and reflection in shallow-water environments. Moreover, the H-type configuration experiences the highest wave forces, whereas the ?-type structure experiences the least. The findings of this study offer valuable insights into the design and analysis of floating breakwaters in offshore environments. © Harbin Engineering University and Springer-Verlag GmbH Germany, part of Springer Nature 2025.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.