Print Email Facebook Twitter Vortical VLF motions under shore-normal incident waves Title Vortical VLF motions under shore-normal incident waves Author De Schipper, M.A. Reniers, A. MacMahan, J. Ranasinghe, R.W.M.R.J.B. Faculty Civil Engineering and Geosciences Department Hydraulic Engineering Date 2012-07-01 Abstract Field observations and numerical model simulations are examined to investigate the magnitude of vortical very low frequency (VLF) velocity fluctuations (i.e. large scale surfzone eddies) under different offshore wave forcing. Observations of vortical VLF motions under shore -normal wave incidence at Duck, NC, USA are re-analyzed and compared with the characteristics of the incident wave spectrum. Long wave periods and narrow frequency spread incident waves were found to coincide with stronger vortical VLF motions. Numerical model simulations investigating the effect of the incident wave parameters in a more isolated way confirm the observed effect of frequency spread and wave period on the magnitude of VLF motions. Variations in incident wave spectrum resulted in changes in the vortical VLF magnitude of the same order as the magnitude of the vortical VLF velocity fluctuations themselves. These results imply that under shore-normal incident waves strong vortical VLF velocity fluctuations in the surfzone are more likely under swell conditions and at swell dominated coasts. Subject surfzone hydrodynamicslow frequency motionstransient rip currentssurfzone eddies To reference this document use: http://resolver.tudelft.nl/uuid:1ed4d8cf-e424-468b-9076-b2dec4841ac7 Publisher Coastal Engineering Research Council ISSN 2156-1028 Source ICCE 2012: Proceedings of the 33rd International Conference on Coastal Engineering, Santander, Spain, 1-6 July 2012 Part of collection Institutional Repository Document type conference paper Rights (c) 2012 The Author(s)Creative Commons BY Files PDF deSchipper_2012.pdf 539.43 KB Close viewer /islandora/object/uuid:1ed4d8cf-e424-468b-9076-b2dec4841ac7/datastream/OBJ/view