Field Measurements of Inhomogeneous Wave Conditions in Bjørnafjorden
Publication: Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 145, Issue 1
Abstract
Due to the complex topography in a fjord, wave conditions differ from those of ocean waves. In this study, characteristics of wave conditions in the Bjørnafjorden in Hordaland County, Norway were thoroughly investigated based on field measurements. Bjørnafjorden is approximately 4,600 m wide and more than 500 m deep, with a complex hydrography and topography. Three Datawell Waveriders (DWRs, Datawell, Haarlem, Netherlands) were deployed to measure the wave data. Due to two ferry routes nearby, the measured raw data were found to be influenced by ship waves. Thus, a band-pass filter based on wavelet and inverse wavelet analyses was proposed and developed to detect and remove ship waves from raw data. The wave data analyzed were measured over approximately 19 months. The wave conditions measured by each DWR were characterized by several parameters, such as significant wave height, average zero upcrossing period, and dominant direction. The values of each wave parameter at each DWR usually differed, which indicates that the wave field in Bjørnafjorden is inhomogeneous. The statistical values of these parameters among the three DWRs were correlated to some extent. Their distribution could not be fitted by a suitable distribution function unless more data were available. The coherence among the three DWRs was fairly low.
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Acknowledgments
This work was supported by the Norwegian Public Road Administration (NPRA) and in part by the Research Council of Norway through the Centre for Ships and Ocean Structures (CeSOS) and Centre for Autonomous Marine Operations and Systems (AMOS) at the Department of Marine Technology, Norwegian University of Science and Technology, Trondheim, Norway. The support is gratefully acknowledged by the authors. The authors acknowledge the NPRA for the permission to publish the measured wave data. Dr. François Beauducel is also acknowledged for writing the original MATLAB function facilitating the use of Shuttle Radar Topography Mission (SRTM) digital elevation model data files.
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Published In
Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 145 • Issue 1 • January 2019
Copyright
© 2018 American Society of Civil Engineers.
History
Received: Dec 6, 2017
Accepted: May 29, 2018
Published online: Sep 20, 2018
Published in print: Jan 1, 2019
Discussion open until: Feb 20, 2019
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