Research On Dynamic Characteristics Of Wave Hydrodynamics In Flexible Plant

The wave and storm surge,in recent years,increasingly endanger the life and property of the coast residents.To protect the safety of people's production and living,it is necessary to build a series of revetment engineering,which can be used to induce the destruction of beach,seawall and wharf structure due to the effect of wave.Plant revetment engineering is one of the most commonly used structures in coastal owing to its capability of safeguarding the landscape and coastal facilities.Plant revetment engineering has a good effect on absorb wave and flow,as well as the beach protection.Meanwhile,it is useful to beautify the environment and maintain ecological balance.An experimental study without practical engineering background is performed on the wave flume based on the investigation of previous researches.The wave dissipation was analyzed according to some factors such as the water depth,incident wave height,plant length,plant density and plant height etc.The vertical velocity distribution and attenuation feature of the plant section,as well as the distribution characteristics of the bed shear stress were also systematically analyzed.The results are as follows:(1)At the same density and height of plant condition,the wave height was decreasing along the direction of wave propagation,but the attenuation coefficient of wave height varied contrary,which increased almost linearly.At the various plant density circumstance,the effect of wave height damping is apparently reduced with the density increasing of flexible plant,meanwhile,the attenuation coefficient of wave height increasingly augmented.On the condition of different plant height,the wave height decreased along the direction of wave propagation and the attenuation coefficient of wave height increased with the increased of the wave height increased.The effect of wave dissipation was best when the plant height and critical water depth were the same.(2)Comparison with the non-vegetation zone,the vertical flow velocity decreased due to the effect on water-flow retardation of the flexible vegetation.The difference value of velocity between the non-vegetation zone and vegetation zone increased slowly with the wave height increased,and the downward trend was found in the zone of the smaller velocity.The difference value of velocity first increased and then decreased with the plant height increased,meanwhile,the velocity decreased significantly when the plant height equal to the immersed water depth.(3)The attenuation coefficient of velocity increased along the direction of wave propagation.It increased with the wave height increased,and decreased with the plant density decreased.The attenuation coefficient of velocity first increased and then decreased with the plant height increased,as well as showed the same variability almost linearly along with the water depth.The distribution of attenuation coefficient of vertical velocity almost uniform with the depth increased of plant zone,and increased obviously near bottom.(4)The maximum value of bed shear stress increased with the wave height increased and decreased almost linearly with the plant width.The maximum value of bed shear stress increased with the plant density decreased.The maximum value of bed shear stress,the rate of curve,and the damping of bed shear stress decreased with the plant height decreased...