EXPERIMENTAL STUDY ON THE CHARACTERISTICS OF CHANGES IN TSUNAMI WAVEFORMS AND WAVE FORCES DUE TO FULUID DENSITY

Abstract

 In this study, a fixed-bed experiment was conducted for black tsunamis with sludge and other sediments, in which tsunamis of turbid water containing bottom sediment with a particle size of a few μm were impacted on a seawall, and the characteristics of waveform and wave force changes due to turbid water densities were confirmed. Three turbid water densities of 1.00, 1.05, and 1.10 g/cm³ were selected in front of the shoreline seawall, and the incident wave from the offshore was commonly generated by fresh water tsunami. The tsunami incident waveforms were varied to three types, the seabed topography was varied to two types, and the position of the seawall was varied to three types, and the effects of these changes were investigated. The results showed that, regardless of the seabed topography and the position of the seawall, the waveform becomes more forward tilted as the turbid water density increases, but the wave force tends to be smaller due to the decrease in tsunami height. However, it was also shown that the wave force may increase depending on the tsunami incident waveform and topography condition because the wave breaking position in front of the seawall changes due to the turbid water density.