| The vegetation in the nearshore area is not continuously and the arrangement in the vegetation is not uniformly distributed.Due to the regrowth,death,or man-made damage of the vegetation,the vegetation is mostly distributed in patches,and the internal arrangement of the patchy vegetation is not uniform.In previous studies,more attention was paid to the attenuation of waves by continuous vegetation,and less research was conducted on the attenuation of wave by patchy vegetation.In this paper,we study the effects of patchy vegetation on wave attenuation and wave induced current.In this paper,a fully nonlinear Boussinesq equation(COULWAVE model)is used to construct the numerical model of this paper by increasing the role of vegetation.Through the verification of physical experiments on different topography with continuous vegetation and patchy vegetation under different wave conditions,the wide applicability of the numerical model is proved.Based on this,numerical experiments were carried out to analyze the effects of changes in patch spacing,the changes of width and density of the same number of vegetation,changes in vegetation diameter,and non-uniform distribution arrangement within the vegetation.The conclusion is that:(1)When changing the distance between vegetation,the wave height is attenuated with respect to the incident wave height,and the variation of the wave height in the vegetation area decreases first and then increases.In the channel,when the spacing is large enough,the wave height gradually decreases and tends to be stable.When the channel spacing is small,the wave height is affected by the vegetation area,which is the same change with the wave height in vegetation area.(2)When changing the density and width of the same number of vegetation,the main factor that affects patchy vegetation is the width,and the density is the main factor that affects the continuous vegetation.(3)The lager diameter of vegetation in the same density,the more attenuation of the wave height for both patchy vegetation and continuous vegetation.(4)When the internal arrangement of the vegetation is not uniform in the flat bottom,the density variation has a greater impact on the internal wave height of the vegetation area.For patchy vegetation,the attenuation of wave height in the uniform distribution of vegetation islarger than that in non-uniform distribution.For the continuous vegetation,the attenuation of wave height in the non-uniform distribution is larger than that in uniform distribution.(5)When solitary wave run on a slope with vegetation,the arrangement of vegetation affects the runup and the velocity of wave-induced current and the inundation height.For the uniformly arranged vegetation area,the greater the density,the stronger the vegetation’s attenuation of the wave,the lower the runup,and the smaller the velocity and the inundation depth.For the same average density of uniform arrangement and non-uniform arrangement,it is the final attenuation of the solitary wave in the uniform arrangement of the vegetation area,and the attenuation degree of the velocity and the inundation depth is better than that of the non-uniform arrangement.In the non-uniform arrangement,the high-low arrangement is better than the low-high arrangement.It has a good guiding significance for the rational arrangement of vegetation areas. |
