Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
3 results
Search Results
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 Hydrodynamic performance of wave energy converter integrated with pile restrained floating structure near a partially reflecting seawall(Elsevier Ltd, 2023) Patil, S.B.; Karmakar, D.The integration of a Wave Energy Converter (WEC) with a Pile-Restrained Rectangular Floating Breakwater (PRFB) in the presence of a partially reflecting vertical seawall is analysed to enhance the hydrodynamic performance and WEC efficiency of the integrated breakwater-WEC device based on small amplitude wave theory using the Boundary Element Method (BEM). The rectangular floating breakwater is designed to have heave motion with a pile-restrained floating structure placed in a position to attenuate the incoming wave in the transmitted region and the linear power take-off (PTO) damping is employed to calculate the absorbed power. The study is performed to understand the effectiveness of wave energy conversion and its hydrodynamic performance due to changes in the seawall's porosity, relative structural width, relative structural draft, wave energy conversion power take-off damping coefficients, and the relative gap of the WEC integrated with PRFB from the seawall. The study demonstrated that in the presence of a fully reflecting seawall, the wave energy extraction is enhanced for the integrated WEC system without compromising the defined threshold wave reflection coefficient but at the expense of a constrained range of wavenumbers that correspond near the system's fundamental natural frequency. Moreover, the capture width ratio is noted to be higher for relatively smaller structural drafts, while the wave reflection coefficient shows precisely the reverse trend. However, under such circumstances, the integrated WEC system operates as a motion-trapping structure, especially when the reflection coefficient of the seawall, CR≥0.75. Thus, the present study will assist the designer in determining the appropriate degrees of efficiency of the WEC device without sacrificing hydrodynamic performance by fine-tuning the hybrid floating breakwater system's geometrical parameters. © 2023 Elsevier LtdItem Hydrodynamic performance of pile restrained U-shaped OWC device using boundary element method(Elsevier Ltd, 2024) Muduli, R.; Patil, S.B.; Karmakar, D.The hydrodynamic performance of a pile-restrained U-shaped Oscillating Water Column (U-OWC) device under the action of normal incident waves is analysed using the Boundary Element Method (BEM). The hydrodynamic parameters, such as the radiation susceptance and conductance coefficients and hydrodynamic efficiency, are analysed for various cases of different structural parameters of U-OWC. It is observed that the theoretical maximum efficiency can be achieved for a wide range of wavenumbers by appropriate tweaking and optimisation of the device geometry. The resonance enables the device to reach the maximum possible efficiency and the phenomenon of obtaining the maximum efficiency of the final optimised geometry is achieved. The shorter length of draft of the device is chosen over longer draft considering the high construction cost as well as efficiency enhancement of the device, even though the longer draft is observed to perform marginally better in a narrow wave number range. The numerical investigation of the theoretical maximum efficiency is observed to be 100% whenever the μ (dimensionless radiation susceptance coefficient) crosses the zero mark. Consequently, the maximum theoretical efficiency is observed close to maximum whenever μ is close to zero. The final optimised geometry consisting of an inward inclined top wall configuration performs best but could be challenging in actual construction. Further, on inclining the bottom wall in the inwards or outward direction does not result in better performance than inclining only the top wall. The present study explores a novel concept of pile-restrained U-OWC kept near the surface and will be helpful in determining the best-performing geometry for the device. © 2023 Elsevier Ltd