Kinematics of Breaking Waves in the Surf Zone

Book excerpt: Measurements were made of the water level fluctuations and horizontal water particle velocities in breaking waves. The breaking waves were identified and classified. The mean value of the height of breaking to depth of breaking was calculated and found to be 0.86 for a composite of the waves measured; the mean ratio values for collapsing, plunging and spilling were 0.84, 0.87 and 0.90, respectively. Probability distributions were plotted for wave heights and horizontal velocities and qualitatively compared with Rayleigh distributions; the wave distributions fit well but velocity did not. The spectra of wave profile and horizontal velocity were calculated and indicated a narrow banded data set. The coherence values between horizontal water particle velocities and wave profile were generally high, indicating that the horizontal particle velocities measured were highly wave-induced. The phase shift at the peak energy frequency was about 40 deg which suggested the presence of reflected waves. (Author).