Short wave breaking effects on low frequency waves

Title

Short wave breaking effects on low frequency waves

 Author

Daly, C.
Roelvink, J.A.
Van Dongeren, A.
Van Thiel de Vries, J.S.M.
McCall, R.T.

Faculty

Civil Engineering and Geosciences

 Department

Hydraulic Engineering

 Date

2010-06-30

 Abstract

The effect of short wave breaking on low frequency waves is investigated using two breaker formulations implemented in a time-dependent numerical model (XBeach): (1) an advective-deterministic approach (ADA) and (2) the probabilistic breaker formulation of Roelvink (1993). Previous research has shown that the ADA breaker model gives different results for the cross-shore pattern of the fraction of breaking waves, which is now shown to affect not only the short wave height but also the short wave groupiness. While RMS short wave heights are comparable to measurements using both breaker models, the ADA breaker model allows higher levels of short wave groupiness into the surf zone. It is shown that this acts as an additional forcing mechanism for low frequency waves in the shoaling and nearshore zone, which, in addition to greater levels of breaking, leads to higher values of wave set-up. These findings are dependent on the complexity of the local bathymetry. For a plane slope, the differences in the low frequency wave heights and set-up predicted by both breaker models are negligible. Where arbitrary breakpoints are present in the field of wave propagation, such as nearshore bars or reefs, the ADA model predicts higher localized set-up, indicative of greater flow over such features. Differences are even more pronounced when the incident wave regime is highly energetic.

 Subject

wave breaking,
low frequency waves,
fraction of breaking waves
wave set-up
wave groupiness
XBeach

 To reference this document use:

http://resolver.tudelft.nl/uuid:8e455008-ba68-425f-985a-7507921fd150

 Source

Proceedings of 32nd International Conference on Coastal Engineering, ICCE 2010, June/July, Shanghai

 Part of collection

Institutional Repository

 Document type

conference paper

 Rights

(c) 2010 Daly, C., Roelvink, J.A., Van Dongeren, A., Van Thiel de Vries, J.S.M., McCall, R.T.
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