Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
4 results
Search Results
Item Coupled dynamic analysis of spar-type floating wind turbine under different wind and wave loading(Springer Science and Business Media Deutschland GmbH, 2021) Rony, J.S.; Karmakar, D.; Guedes Soares, C.G.In the present study, the coupled dynamic modelling of three different configurations of spar platform is performed using time-domain aero-servo-hydro-elastic simulation. The spar platforms are coupled with 5 MW NREL floating wind turbine and mooring sub-models. The coupled aero-servo-hydro-elastic simulation is performed using the simulation tool FAST with WAMIT as the sub module to obtain frequency domain hydrodynamic characteristics. The major emphasis is given to analyse the Response Amplitude Operators (RAOs) to understand the stability of the structures. The responses are calculated for surge, sway, heave, roll, pitch and yaw motions. The study determines the performance of the structure under the wind load developed for the turbine support structure on analysing the tower base forces and moments. The analysis for three different configurations of spar platform is performed for various environmental conditions of North Sea. The studies observed that the responses of the platforms tend to increase with increase in wind speed and wave height. Further, it is observed that surge and pitch motion is dominant for all the three configurations of spar platform. The present study provides an insight into the power performance, structural integrity and dynamic motions of the floating wind turbine under various operational and survival conditions which help the designers to develop better design standards. © 2021, Sociedade Brasileira de Engenharia Naval.Item Performance of a hybrid TLP floating wind turbine combined with arrays of heaving point absorbers(Elsevier Ltd, 2023) Rony, J.S.; Karmakar, D.In the present study, the hydrodynamic performance of circular and concentric arrangements of cone-cylinder-type heaving point absorbers around a Submerged Tension-Leg Platform (STLP) is analysed using the numerical model in the frequency domain based on the potential flow theory. The presence of the Wave Energy Converters (WECs) around the STLP floating wind turbine platform affects the hydrodynamic performance of the hybrid floating platform. So to illustrate the effects of WECs on the platform, the ratio of hydrodynamic coefficients for a single WEC system to that for a hybrid system is analysed. An array of heaving point absorbers is placed in circular and concentric patterns to understand the performance of heaving point absorbers in the absorption of wave energy. The cone-cylinder type heaving point absorber is selected for the present study as they yield more power as compared to other shaped point absorbers. The study compares the wave power absorption of each point absorber around the platform for irregular wave conditions of the North Sea. The effect of incoming waves is illustrated by analysing four different wave heading angles. To quantify the performance of the WECs in an array, the q-factor and coefficient of variation are studied for each array at different sea states. The study suggested the best possible arrangement pattern for wave power absorption and power uniformity among the floaters in the array. The study performed will be helpful in the design and analysis of the possible arrangement of point absorbers around the floating wind turbine platform for wave power absorption. © 2023 Elsevier LtdItem Dynamic analysis of a semi-submersible offshore floating wind turbine combined with wave energy converters(Taylor and Francis Ltd., 2025) Sebastian, B.; Karmakar, D.; Rao, M.Hybrid wind–wave energy systems harness both offshore wind and wave energy resources using a shared floating platform, reducing capital and operational costs through common infrastructure. The present study numerically investigates the dynamic performance and power absorption of three hybrid concepts combining the DeepCwind Semi-submersible Platform (SSP) with (i) Oscillating Water Columns (OWC), (ii) Torus Wave Energy Converter (WEC), and (iii) Flap-type WEC. Frequency-domain analyses using WAMIT and time-domain simulations using OpenFAST are performed to assess platform motions, tower base moments, mooring tensions, and WEC power output for different sea states. The integration of WECs significantly improves the hydrodynamic behaviour of the DeepCwind SSP. Flap-type WECs demonstrate the best dynamic performance, reducing heave and pitch by up to 68% and 58%, and mooring tension by 54%. The OWC system achieves the highest power absorption and a 55% capture width ratio, but increases surge and pitch motions by 6% and 27%, respectively, on introducing additional loads on the system. © 2025 Informa UK Limited, trading as Taylor & Francis Group.Item Dynamic analysis of a TLP-type floating wind turbine combined with OWC wave energy converter(Springer Nature, 2025) Sebastian, B.; Joju, A.; Karmakar, D.The present study examines the dynamic effects of integrating oscillating water column wave energy converters on the offset columns of a tension leg floating wind turbine platform in an asymmetric and symmetric configuration. Two configurations are considered, featuring two and four oscillating water columns combined with the tension leg platform supporting a 5 MW wind turbine. The hydrodynamic analysis of the combined wind-wave energy system uses a linear diffraction-radiation tool to compute hydrodynamic coefficients and wave excitation forces in the frequency domain. The coupled dynamic responses of the hybrid platforms are evaluated in the time domain under various irregular sea states, using an aero-hydro-servo-elastic simulation tool. The performance of the hybrid systems is compared with a baseline floating wind turbine platform to quantify changes in dynamic responses. Power absorption of the oscillating water columns is computed using a linear power take-off system. The findings indicate that adding oscillating water columns leads to a slight increase in the heave and pitch motions of the platform. The system with a diagonally placed two-oscillating water column configuration demonstrates higher efficiency, achieving a maximum capture width ratio of 57%. This study provides valuable insights into the feasibility of hybrid offshore renewable energy concepts. It supports the design and implementation of integrated wind-wave systems to deliver clean and sustainable energy. © The Author(s), under exclusive licence to Sociedade Brasileira de Engenharia Naval 2025.