Journal Articles
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/19884
Browse
3 results
Search Results
Item Numerical investigation on the wave dissipating performance due to multiple porous structures(Taylor and Francis Ltd., 2021) Venkateswarlu, V.; Karmakar, D.Gravity wave interaction with porous structures is investigated under the assumption of linearized wave theory. Multiple porous blocks of finite thickness with finite spacing are investigated under the action of oblique ocean waves considering leeward unbounded region and confined region. The eigenfunction expansion method is employed to analyse the effect of multiple-confined regions in the trapping of oblique waves. The study outcomes are validated with numerical and experimental results available in the literature. The friction factor and the inertia effect of the porous medium are considered and different porosity conditions are adopted to determine the wave reflection coefficient, transmission coefficient, wave dissipation and wave force impact on the leeward wall. The functional efficiency of multiple fully extended porous structures is studied for different values of porosity, water chamber length, angle of incidence, friction factor and spacing between the porous blocks. The seabed is assumed to be uniform impermeable bottom and uneven bottom (step approximation is adopted). The study demonstrates that the better wave blocking is achieved with the increase in the series of porous structures and the confined regions can be used effectively for the trapping of oblique waves. The present study will be helpful in the design of porous structures for security of coastal facilities and coastal structures in offshore environment. © 2019 Indian Society for Hydraulics.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 Numerical investigation of offshore wind turbine combined with wave energy converter(Springer Nature, 2023) Rony, J.S.; Sai, K.C.; Karmakar, D.The coupled dynamic analysis is performed for three different types of offshore floating platforms combined with a wave energy converter (WEC) mounting a 5-MW NREL (National Renewable Energy Laboratory) wind turbine. The Response Amplitude Operators (RAOs) are analysed for the three concepts of combined wind and wave energy platforms for different wind and wave conditions. The hydrodynamic performance for the three different platforms is conducted considering different load cases. The time domain aero-servo-hydro-elastic tool is used to study the motion responses of the combined system under real operational conditions. The platform’s responses are observed to increase with the increase in the wind speed. In the case of floating hybrid platform, surge responses are minimal for the hybrid spar-tours combination for any load case condition. Minimum surge and sway ensure higher wind power absorption. The study further focuses on the tower base forces and moments to study the impact of wind and waves on the combined floater. Fore-aft shear forces and fore-aft bending moments are higher for the platforms indicating the importance of wind-wave loading. The time domain responses are further used as the transfer function to predict the most probable maximum values of motion amplitude expected to occur during the life-time of the structure which can be used for designing a floating wind turbine (FWT) against overturning in high waves. The long-term models are constructed using various short-term situations expected to occur during the structure’s life-time and weighing them appropriately. The long-term distribution uses North Atlantic wave data, and short-term responses are calculated considering Rayleigh distribution. A brief comparative study of the three combined offshore floaters is performed to understand the structural integrity, power performance and dynamic motions of the floating wind energy platform combined with WECs. © 2023, The Author(s), under exclusive licence to Sociedade Brasileira de Engenharia Naval.