SET-UP DRIVEN UNDERTOWS ON A BARRED BEACH

Proceedings of the International Conference on Coastal Engineering

Philip D. Osborne¹  Brian Greenwood¹ 

[1] Scarborough College Coastal Research Group, University of Toronto

关键词: barred beach;    set up;    undertow;   

DOI  :  10.9753/icce.v22.%p

学科分类：建筑学

来源: Coastal Engineering Research Council

【 摘 要 】

Field measurements of cross-shore velocity and water surface elevation from a natural barred surf zone during two storm events confirm the presence of undertow. The undertow is characterized by: i) mean cross-shore velocities reaching 0.20 m s"1 and directed offshore; ii) mean cross-shore velocity decreasing towards the surface with occasional reversals in the mean flow to a landward direction in the upper water column; iii) a strongly oscillatory velocity field with speeds increasing towards the surface and a distinct landward skewness superimposed. The undertow is strongly correlated with set-up of the mean water surface. The set-up is characterized by: i) increasing values shoreward with perturbations closely following topography indicative of a primary forcing by waves; ii) maxima (0.35 m in the inner system) occurring over the bar troughs in association with decreasing wave height over the preceding bar crest as predicted by theory and laboratory experiments.

【 授权许可】

Unknown