Document Type

Thesis - University Access Only

Award Date

2003

Degree Name

Master of Science (MS)

Department / School

Civil and Environmental Engineering

First Advisor

Francis

Abstract

This study is concerned with the breaking and transformation o f irregular waves on a plane slope in a laboratory surf zone. The incident wave pattern was produced by a wave maker using the JONSWAP wave spectrum. Input parameters were selected to produce a broad range of wave frequencies. The same 15-minute wave pattern was used for all trials of the experiment. From this wave pattern only 10 minutes of wave elevation data were collected by the wave gages. Two of these resistance type wave gages were mounted on an instrument carriage that allowed for measuring the wave elevation at 11 different locations along the flume. All of the measurements were synchronized with the start of wave generation. From the measured wave elevation time series various wave characteristics could be determined, such as the wave height, wave period, wavelength, and phase velocity for each individual wave in the wave time series. From the entire 10-minute wave record a representative wave group was selected to do a complete wave-by-wave analysis. Information extracted from this wave group included the variations in wave height and wave shape parameters within the surf zone. It was found that the wave period, wavelength, and wave speed had wider variations inside the surf zone than outside of it. The low-frequency motion that was generated in the wave breaking process affected the values of the wavelength, wave period and wave speed in the inner surf zone. Individual waves were transported by the orbital velocities of the long waves. This caused variations in wave speed, which in tum affected the wavelength and period. Statistical analysis was carried out on the entire wave record as well as on the wave group. The mean and standard deviation values of various wave shape parameters from the entire wave record were compared to those from the selected wave group. It was found that the mean and standard deviation values for the wave shape parameters compared well between the wave group and the entire wave time series. When comparing these to the individual waves there were some variances but when the individual waves were in the inner surf zone the wave shape parameters typically fell within the same trends as the average values of the entire wave time series and wave group. Overall this study provided a wealth of new information and data for the evolution of breaking waves in a laboratory surf zone. This particular study only touched the surface of what can be learned from this data set, so further in-depth analysis should be done with the data collected during this experimental process.

Library of Congress Subject Headings

Waves -- Analysis.
Water waves -- Analysis.

Publisher

South Dakota State University

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Rights Statement

In Copyright