Experimental Study on the Characteristics of Flow Induced by an Internal Solitary Shoaling Wave

• Main Authors: Jen-Shiun Lin, 林振勛
• Other Authors: 林呈
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/99404161979994356865

碩士 === 國立中興大學 === 土木工程學系所 === 96 === The purpose of this study is to understand the flow field of internal solitary wave running up and down along a sloping bottom. The experiments of internal solitary waves were carried out using stratified two-layer fresh/saline water in the wave flume. The slope of sloping-bottom model was set with a fixed angle of 30 °. The experiments were conducted under the same density ratio ( ) and the same thickness ratio of the upper and lower layers (h1/h2 = 7). The internal solitary waves were generated by changing different potential energies ( = 5 cm, 10 cm, 15 cm, and 20 cm). The dye was added into water for flow visualization. The particle image velocimetry (PIV) was used to measure quantitatively the velocity distribution of internal solitary waves. The high-speed camera was used to capture the images of flow field. The validations of the incident internal solitary wave was carried out in absence of obstacle. Good agreement was obtained from the comparison between the wave shape of the internal solitary wave and the Kdv or mKdv theory. The horizontal velocity was validated by using FLDV. The wave propagation processes, including run-up and run-down, were observed by flow visualization. The measuring coordinate was tilted to an angle of 30 ° for the measurement of velocity distribution along the slope. The characteristics of velocity profile were investigated in detail with dimensionless time T during the run-up and run-down processes. Using shear layer concept proposed by Lin et al. (2008), velocity distribution of the internal solitary wave was analyzed for run-up and run-down processes. The velocity and length scales were clearly defined using hyperbolic tangent function. The similarity profile of velocity distribution for shear layer has been found in the study.