Abstract:
The study of rip currents by intersecting waves is helpful to the comprehensive study of disaster mechanisms and risk assessment. To better understand the characteristics of rip currents controlled by hydrodynamic forcing and longshore topographical variability,an experimental study on rip currents by intersecting waves over barred beaches with rip channels is conducted. The investigation focuses on the distribution characteristics of rip currents resulting from intersecting waves and longshore topographical variability. Analytical results of velocity distribution measurements by acoustic Doppler velocimeters are presented for the distribution characteristics of rip currents on barred beaches with rip channel. The location and width of rip currents are controlled by rip channel and wave nodes,and the length of the rip currents depends on the wave height and coastal slope. The driving force of rip currents without rip channel is primarily determined by the alongshore pressure gradient of the wave setup caused by intersecting waves. By contrast,the driving force of rip currents with rip channel is determined by both the alongshore pressure gradient of the wave set-up and the radial stress gradient,and the relative magnitude of the two values depends on the wave period.