Experimental study of water waves : nonlinear effects and absorption
Experimental study of water waves : nonlinear effects and absorption
复制标题
水波的实验研究：非线性效应和吸收
DOI：
--
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
E. Gutiérrez
中科院分区：
文献类型：
--
作者：
E. Gutiérrez
本文对非线性水波的传播进行了实验研究。第一部分着重于非线性水波通过水下台阶时的时空测量。时空分辨测量允许我们在二阶分离不同的分量，这与理论上的非线性多模态模型进行比较。通过测量二次谐波的拍长，证实了高阶表面张力的重要贡献。在相同的条件下，在通道的端部增加反射壁设置一个矩形槽与淹没的步骤，其中的低频模式的激励产生准周期动力学。同时，对表面波小尺度实验中应考虑的问题进行了研究。在浅水中，底摩擦对水波的阻尼有很大的影响。对随机分布的波测量了这种依赖性，揭示了这种效应的相对贡献。此外，动态的接触线起着显着的作用时，波振幅小，边界附近，都与毛细管长度。我们通过实验观察到边界的润湿如何改变反射和波前曲率。最后一部分是窄波导中耦合谐振腔对理想波吸收的测量。由偏离通道轴的圆柱产生的俘获模被激发产生吸收。
This thesis presents an experimental investigation on the propagation of nonlinear water waves. The first part focuses on the space-time measurements of nonlinear water waves, when it passes over a submerged step. The space-time resolved measurement allows us to separate the different components at the second order, which are compared with a theoretical nonlinear multi-modal model. The important contribution of the surface tension at higher orders is verified by measuring the beating length of the second harmonic. In the same conditions, the addition of a reflecting wall at the end of the channel sets a rectangular tank with submerged step, where the excitation of low-frequency modes yields a quasi-periodic dynamics. Concurrently, a research about aspects that have to be considered in small scale experiments of surface waves has been carried out. In shallow water, the damping of water waves is highly influenced by the bottom friction. This dependence was measured for randomly distributed waves, revealing the relative contribution of this effect. Moreover, the dynamic of the contact line plays a significant role when the wave-amplitude is small and the boundaries are near, both in relation to the capillary length. We observed experimentally how the wetting of the boundaries changes the reflection and the wave-front curvature. The final part covers the measurement of perfect wave absorption by a coupled resonator in a narrow waveguide. The trapped modes generated by a cylinder shifted from the channel axis were excited to generate the absorption.