Asymmetry in Directional Spreading Function of Random Waves due to Refraction
Publication: Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 136, Issue 1
Abstract
In this study, a more general directional spreading function is developed that allows for asymmetric directional distributions. For multidirectional random waves that approach the shore obliquely over a planar slope, we demonstrate that directional asymmetry is generated due to wave refraction. The asymmetry created by refraction increases with the offshore peak wave direction. The present spreading function is compared to a preexisting symmetric spreading function and is shown to better capture changes in the directional distribution that occur in a refracting, random wave field. Finally, the new asymmetric spreading function is compared to a long time series of wave directional spectra measured at a nearshore field site. The results demonstrate that refraction-induced asymmetry is common in the nearshore and the asymmetric spreading function gives an improved analytic representation of the overall directional distribution as compared to the symmetric function.
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Acknowledgments
This work was supported by the Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea government (MEST) (Grant No. UNSPECIFIEDR01-2008-000-20442-0). We thank the staff at the FRF for making their extensive observations available online and all of their efforts at ongoing data collection. We also thank Patricio Catálan for providing code to read the measured spectra.
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Information
Published In
Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 136 • Issue 1 • January 2010
Pages: 1 - 9
Copyright
© 2010 ASCE.
History
Received: Aug 16, 2008
Accepted: Jan 16, 2009
Published online: Feb 24, 2009
Published in print: Jan 2010
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