Author(s): T. Liiv; U. Liiv
Linked Author(s):
Keywords: Breaking waves; 2D laboratory study; Unsteady characteristics; Spectrum analysis
Abstract: Two dimensional investigations of the breaking wave turbulent characteristics have been carried out in a glass walled wave flume of the Laboratory of Hydraulics of the Tallinn Technical University. Experimental results show that inside breaking waves are intermittent zones with accelerations and decelerations. The experiments smooth and rough bed of the models and show that the bottom roughness affects strongly the wave propagation, shear and turbulent characteristics of the breaking waves. Spectrum analysis of the local turubulence are presented. lnertial forces caused by the unsteady motion of the waves are acting to the turbulent characteristics differently during the period of acceleration and deceleration of the waves: acceleration causes pressing down the values of the instantaneous turbulent intensities of the shear, but during deceleration the corresponding values are higher than those obtained from the steady flow investigations. The analysis of the spectra inside the surf zone has been carried out. The spectral forms of the velocities depend on the nonstationary characteristics of the turbulence.
Year: 1999