Abstract
This paper presents results from an experimental work to investigate wave loading on the main column of a tripod offshore wind turbine in regular and random wave conditions in the Large Wave Flume in Hannover, Germany. In-line force coefficients (drag and inertia coefficients) are estimated from the measured pressures on the tripod surface at different elevations along the length of the column. The wave kinematics are estimated by using different wave theories. Methods of max-min and least-squares (simplified by fit on wave-by-wave basis) are applied to determine the force coefficients. It is found that the drag coefficient, CD, has larger scattering than the inertia coefficient CM. The drag coefficient CD is very sensitive in its estimation. The mean values of CD vary from 0.61 to 0.95 with standard deviation of 0.17 to 0.18. The inertia coefficient, CM, shows small scatter and has its mean value varies from 1.15 to 1.23 with a standard deviation of 0.07 to 0.08 for the tested regular waves. The tested spectral waves give the inertia coefficient CM varies from 0.96 to 1.31 with standard deviation of 0.41 to 0.43.
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Acknowledgements
The author gratefully acknowledges the support of the German Federal Environment Ministry (BMU) within the funded project “Ganzheitliches Dimensionierungskonzept für OWEATragstrukturen hinsichtlich Lasten, Langlebigkeit, Gründung und Gesamtstruktur (GIGAWIND alpha ventus - LUH)” (BMU code 0325032/A). Project details and cooperation partners can be collected from www.gigawind.de.
The author acknowledges the support of the National University of Civil Engineering, Vietnam for attending the APAC 2019 conference in Hanoi.
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Mai, T. (2020). Estimation of Drag and Inertia Coefficients for a Tripod Support Structure of Offshore Wind Turbine. In: Trung Viet, N., Xiping, D., Thanh Tung, T. (eds) APAC 2019. APAC 2019. Springer, Singapore. https://doi.org/10.1007/978-981-15-0291-0_149
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DOI: https://doi.org/10.1007/978-981-15-0291-0_149
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