Study on the Flow and Force Characteristics of the Dam-break Flow on a Bridge Deck

• Main Authors: Yu-Jie Pan, 潘雨婕
• Other Authors: Ching-Piao Tsai
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/08413527084735813481

碩士 === 國立中興大學 === 土木工程學系所 === 103 === Morakot Typhoon hit Taiwan on August, 2009, brought breaking record of rainfall in central and southern mountainous areas. Rocky collapse caused blockage and a barrier lake, then the barrier lake was broken by continuous rainfall and caused dam-break flow. Dam-break flow with high-speed impact bridge structure at the downstream, and resulted bridge deck damaged. The study used hydrodynamic calculation software called FlOW-3D, which is based on three-dimensional momentum equation and volume of fluid (VOF). In this study, a numerical simulation was investigated the flow and force of the dam-break flow on a bridge deck. Through comparison of numerical simulation and experimental results showed that it’s accurate to simulate dam-break flow field and bridge deck force by using k-? turbulence model This study set a fixed water level and an electric gate at the upstream to simulate dam-break flow when the gate was opened. The results showed when there was no structure at the downstream, vortex core would move to the downstream with slow speed and dissipate gradually. And vortex core would transfer far away with lower water depth at the downstream. Then this study set the bridge deck at the downstream. The results showed that when the water depth was lower at the downstream , turbulent kinematic energy(TKE)、dissipation of turbulent kinematic energy(DTKE) and vorticity around bridge deck would be more obvious. Through analysis of force distribution found that force impacted by the dam-break flow depended on the distance from the bridge deck and the initial free surface. That means when the distance is closer, the impact force will larger.