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

研究了结构(竖直刚性结构和吸波型结构)对非线性规则波/Q不规则波的反射特性。通过将波浪水槽分成两个通道的方法进行了实验。渠道两端有竖墙和由砾石和草球组成的吸水坡面。在将入射和反射波与结构前面的波分开的情况下，通常使用Healy方法。但是，它只能用于线性或无限大的波浪场。首先，通过测量竖直刚性墙前方节点的振幅，阐明了Healy方法的应用范围，在应用范围的外侧，Healy方法得到的反射系数与由Tad；Baksh&Keller驻波理论计算的表观反射系数相吻合。其次，用电减法求出了反射系数。这些系数可以根据每个航道中距离造波机相同距离的两个波型来计算。计算的反射系数随距离刚性墙的距离而变化。在刚性墙的情况下，由驻波节点处测得的波形计算的反射系数接近1.0。由回线测得的波形计算出的系数均大于1.0，这是由于入射波和反射波的相互作用造成的。结果表明，利用驻波和部分驻波节点处测得的波形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.