AbstractBreaking waves are a very complicated phenomenon associated with high energy transfer rates and turbulence levels and can create tremendous loads when impacting on a structure. Therefore an exact understanding of the wave breaking process is of major interest in coastal and offshore engineering research. In this context the point of breaking inception is of critical importance, e.g. for breaking wave impact studies, but despite lots of research efforts still no objective and unique criterion exists and the breaking point needs to be estimated by tedious and subjective analysis of video data. The Phase-Time Method (PTM), as introduced by Huang et al. (1992), was shown to be able to overcome these discrepancies and to provide an objective method for the determination of the point of breaking inception as demonstrated by Zimmermann and Seymour (2002) and Irschik et al. (2010). However, their threshold based approaches still seem to be slightly ambiguous and lack general validity. In the present work the PTM and the suggested breaking detection methods will be reviewed and thoroughly evaluated. The most critical issues will be addressed and new approaches to interpret the PTM data will be proposed.
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