Journal of Marine Sciences ›› 2022, Vol. 40 ›› Issue (1): 33-41.DOI: 10.3969/j.issn.1001-909X.2022.01.004

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Experimental study on nonlinear characteristics of waves within inner surf and swash zones

In this study, Particle Image Velocimetry (PIV) and Wave Gauge (WG) were used to measure the wave height, wave velocity and other hydrodynamic parameters within inner surf and swash zones under three slopes. Based on the second-order spectrum method, the probability density distribution of wave height and velocity between different sections, as well as high-order nonlinear statistical variables such as skewness, asymmetry and kurtosis were analyzed. The results show that the wave height and velocity deviate from the normal distribution, the skewness and kurtosis of wave height decrease first and then increase during the nearshore propagation, the asymmetry increase first and then decrease, and the nonlinear characteristics of wave height are not affected by the slope. The velocity in the three cases shows different nonlinear distribution characteristics. In the steep slope and composite slope, section distribution of velocity skewness characteristics are not obvious. Only the vertical distribution of velocity skewness at each section of gentle slope increases first and then decreases. The velocity asymmetry of the three cases increases first and then decreases with the increase of the distance from the bed.   

  1. 1.School of Hydraulic and Environmental Engineering，Changsha University of Science ＆ Technology, Changsha  410114, China; 
    2.Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province, Changsha 410114, China; 
    3.International Research Center of Water Science ＆ Environmental Engineering, Changsha University of Science ＆ Technology, Changsha 410114, China
  • Online:2022-03-15 Published:2022-03-15

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Abstract: In this study, Particle Image Velocimetry (PIV) and Wave Gauge (WG) were used to measure the wave height, wave velocity and other hydrodynamic parameters within inner surf and swash zones under three slopes. Based on the second-order spectrum method, the probability density distribution of wave height and velocity between different sections, as well as high-order nonlinear statistical variables such as skewness, asymmetry and kurtosis were analyzed. The results show that the wave height and velocity deviate from the normal distribution, the skewness and kurtosis of wave height decrease first and then increase during the nearshore propagation, the asymmetry increase first and then decrease, and the nonlinear characteristics of wave height are not affected by the slope. The velocity in the three cases shows different nonlinear distribution characteristics. In the steep slope and composite slope, section distribution of velocity skewness characteristics are not obvious. Only the vertical distribution of velocity skewness at each section of gentle slope increases first and then decreases. The velocity asymmetry of the three cases increases first and then decreases with the increase of the distance from the bed.


Key words: swash zone, skewness, asymmetry, kurtosis, nonlinear characteristics

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