Browsing by Author "Abdulla, K."

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    Dissipation of Gravity Waves Due to Submerged Porous Plate Coupled With Porous Structures
    (American Society of Mechanical Engineers (ASME), 2023) Krishna, K.R.A.; Abdulla, K.; Karmakar, D.
    The present study focuses on wave trapping due to the submerged horizontal porous plate combined with the bottom-standing porous structure and surface-piercing porous structure. The submerged plate thickness is considered to be negligible as compared to the incident wavelength and water depth, and the porous structure is considered to be of finite width. The study is performed based on the eigenfunction expansion method, and the wave interaction with the combined structure is investigated using the small amplitude wave theory. The orthogonal mode-coupling relation is used to analyze the wave interaction with the combined structure. The reflection, transmission, and dissipation coefficients along with wave force on the porous structure are investigated to analyze the hydrodynamic performance of the composite porous breakwater system. Further, the effect of porosity of submerged plate and structure, submergence depth of plate and structure, angle of incidence, and the submerged plate length are investigated to analyze the effective wave dissipation by the composite breakwater. In addition, the comparative study of the numerical method is performed with the results available in the literature. The study noted that the wave damping due to the submerged porous plate backed by surface-piercing porous structure is more as compared to the submerged porous plate backed by the bottom-standing porous structure. The study performed will be helpful to scientists and engineers in the design of suitable composite breakwater systems and also assists in selecting the best structural configuration for attenuation of wave height and to protect the offshore facility from high waves in the coastal region. © 2023 American Society of Mechanical Engineers (ASME). All rights reserved.
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    Wave Energy Damping due to Coupled Porous Structure and Submerged Porous Plate
    (Editorial Board of Journal of Harbin Engineering, 2023) Athul Krishna, K.R.; Abdulla, K.; Karmakar, D.
    The present study investigates the wave-damping characteristics due to the combination of bottom-standing porous structure, submerged porous plate, and fully-extended porous structure of finite width using the small amplitude wave theory. The hydrodynamic characteristics such as reflection, transmission, and dissipation coefficients are determined to analyse the wave energy dissipation by the composite breakwater using the matched eigenfunction expansion method and orthogonal mode-coupling relation. Darcy’s law is incorporated to the flow through porous media. The composite breakwater system is investigated experimentally to validate and compare the numerical results with the physical model study. The complex porous effect parameter for the submerged plate is incorporated in the numerical analysis, which represents the reactance and resistance of the porous structure. The wave forces on the submerged plate and porous structure for the composite breakwater are investigated by considering the effects of changing parameters such as structural porosity, plate submergence, angle of incidence, width of the submerged porous structure and distance between the structures. The study illustrates that the increasing width of the fully-extended porous structure improves the performance of the breakwater system. The proposed study on the composite breakwater yields an useful information for wave energy attenuation, which can be designed and implemented in coastal and harbour areas to achieve wave tranquillity. © 2023, Harbin Engineering University and Springer-Verlag GmbH Germany, part of Springer Nature.