Mass and energy transport with the presence of two sinusoidal travelling waves

• Main Authors: Ru-Jyun WANG, 王如君
• Other Authors: 丁肇隆
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/14501474774287270293

碩士 === 國立臺灣大學 === 工程科學及海洋工程學研究所 === 100 === Interactions between two sinusoidal waves were investigated in this thesis. The wave fields were generated by two different ways. One is a 2 Hz wave chased by a 1 Hz wave. The other one is generated by a 1 Hz wave propagating over a submerged rectangular step. A PIV measurement system was used to measure wave fields. The wave forms, velocity field and particle trajectories of wave fields were measured. The kinetic and potential energies of the two-wave propagation were calculated and compared with the theoretical values. Also, the averaged mass transport speeds were calculated. From the experimental results, it showed that the particle velocity of two travelling sinusoidal waves, is slower than the particle velocity generated by a wave passing through the submerged obstacle. The two travelling sinusoidal waves were generated both in weakly non-linear range. Therefore, their potential and kinematic energy are similar and very close to the values predicted by linear theory. However, the kinematic energy of the wave passing through a submerged obstacle is larger than its potential energy. Due to the existence of tank end, the mean mass transport velocity is negative but nearly zero. Finally, it was observed that there exists energy transfer between two waves in space. The most apparent transfer effect occurs when the amplitudes of two waves are nearly equal.