DENG Bin 1,2,3 JIANG Changbo 1,2,3 LI Zhiwei 1,2,3 LIU Xiaojian 1
JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 68-77.
The characteristics of complex water flow in the swash zone are the key to the study of material transport in the nearshore zone, in which the diachronic variation of wave elements has complex nonlinear wave characteristics of non-stationarity, asymmetry and multi-scale variation, and so on.The action period and trend law of the wave element were analyzed, it is very important in order to understand the complex dynamic process of water and sediment in the swash zone.Based on the dam-break principle, a flume experiment was carried out to study the nonlinear wave characteristics of the scour current belt under the action of the surge wave with different slope.EEMD and HHT methods were used to analyze the experimental wave data, and the normalized wave energy spectrum, marginal energy spectrum and marginal energy spectrum were obtained, and the influence of water fluctuation on shoreline was analyzed with power spectral density.The results show that the wave energy of the current zone is mainly concentrated at the low frequency, which is lower than 1 Hz.Under the three experimental conditions, the maximum instantaneous energy gradually decrease along the shoreline direction.The maximum instantaneous energy appears and the currents have the strongest effects on shoreline, when the currents act on the shoreline for 2-3 s, 3-5 s and 3-6 s respectively.The steeper the slope of the beach is, the earlier the maximum instantaneous energy value appears, the greater the effect on the beach surface is.