Reflection Properties of Non-liner Irregular for Wave due to Wave Absorber Type Structure

本文研究了结构（垂直刚性结构和吸波型结构）对非线性规则/不规则波的反射特性。实验是通过将波浪槽分成两个通道来进行的。沟渠的末端有垂直的墙和由砾石和草球组成的吸收坡。在将入射波和反射波从结构前面的波中分离出来的情况下，通常使用希利的方法。但是，它只能用于线性或无穷小的波。首先，通过测量垂直刚性墙前方节点的振幅，明确了希利法的适用范围，在适用范围的外侧，希利法得到的反射系数与Tad计算的明显反射系数吻合；baksh & Keller驻波理论。其次，采用电减法确定反射系数。这些系数可以从每个通道中离波源相同距离处的两个波廓线计算得到。计算得到的反射系数随与刚性墙的距离而波动。刚性壁面时，驻波节点实测波廓线计算出的反射系数接近1.0。根据环上实测波廓线计算出的系数大于1.0，这种现象是由于入射波和反射波相互作用造成的。阐明了在驻波和部分驻波节点测得的波廓线计算电减法是获得准确反射系数的一种很好的方法。

This research deals with the reflection properties of non-linear regular/Qirregular wave due to structures ( vertical rigid structure and wave absorbertype structure). Experiments were carried out by means of dividing a wave tank into two channels. The ends of the channels had vertical wall and absorbing slope made from gravels and grass balls. In the case of separating incident and reflecting waves from waves in front of the structure, Healy's methodis usually used. But, it should by used for only linear or infinitesmal wave. At first, the author clarified the application limit of Healy's method by measuring the amplitude of node in front of the vertical rigid wall, and in the outer side of the application limit, reffection coefficients obtained from Healy's method coincide with the apparentreflection coefficients calculated from Tad; baksh & Keller's standing wave theory. Next, author determined the refiection coefficients by electrical subtraction method. The coefficients can be calculated from two wave profiles at the same distance from wave generator in each channel. The calculated reflection coefficients fiuctuated in accordance with distance from rigid wall. In the case of rigid wall, the reflection coefficients calculated from wave profiles measured at the node of standing wave are nearly 1.0. The coefficients calculated from wave profiles measured at the loop are larger than 1.0 and this phenomena occured due to the interaction between incident and reflected waves. It was clarified that electrical subtraction method calculated from the wave profiles measured at the node of standing and partial standing waves was very good method in order to get accurate reflection coefficient.