טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentUria Itay
SubjectIn search of a Kinematic criterion for the breaking of
shoaling waves
DepartmentDepartment of Civil and Environmental Engineering
Supervisor Dr. Liberzon Dan
Full Thesis textFull thesis text - English Version


Abstract

An experimental study was conducted with the aim of validating the Lagrangian kinematic criterion (LKC) introduced by Shemer and Liberzon (2014) for the case of breaking of shoaling waves. Monochromatic wave trains were generated in a large wave flume and allowed to shoal and break naturally on an artificial inclination changeable shore, thus allowing inspection of a range of slopes. Instantaneous horizontal Lagrangian water surface velocity was measured by Particle Tracking Velocimetry and compared to the instantaneous propagation speed of the crest on a verge of breaking, the latter calculated using time series produced by resistance type wave gauges staged along the flume. The inception of a breaker was found to occur when the monotonically increasing horizontal water velocity on the crest, during the process of steepening, approached that of the slowing steep crest, thus confirming the LKC for shoaling conditions.

In addition, an objective method of breaking detection was developed utilizing the Phase-Time Method and wavelet analysis, by recognizing a specific pattern in the instantaneous local frequency fluctuations. These results' main expected contributions are the formation of an applicable criterion, accompanied by wave breaking detection method independent of human decision, which will aid in further validation of the LKC to other waves' fields.