潰壩流撞擊直立平板之流況分析

凃秉杰(Bing-jie Tu)

指導教授 ： 周憲德

國立中央大學/工學院/土木工程學系/碩士(2015年)

摘要

土石流及海嘯的流動過程中都屬於潰壩流的一種，而這些大自然災害破壞力相當巨大，對於人民的財產安全會造成嚴重的損失，而這些損失往往都是難以估計的，因此防範這些大自然的災害就變成重要的課題。
本研究經由二維渠槽進行一系列的潰壩流實驗，由於坡地溪床的縱坡約6o~9o，因此實驗除了水平底床的潰壩流實驗以外，也將渠槽裝置一個6o的傾斜底床來進行比較。潰壩流實驗採用五個不同的潰壩高度撞擊垂直平板，分析垂直平板不同高程處的壓力分佈、波前速度以及撞擊高度。實驗結果發現在越接近底床處越容易發生最大壓力，且也有較大的誤差，而傾斜底床測得最大的壓力約為水平底床1.2~1.5倍。裝置傾斜底床後流體波前的瞬時速度會越接近2√gH。流體撞擊垂直平板的高度可以得知壓力是否會有明顯峰值的現象發生，顯示撞擊高度與壓力的形成方式有很大的關係。

關鍵字

潰壩流 ； 湧浪 ； 垂直牆 ； 衝擊壓力

並列摘要

The movement of tsunamis and dam-break flows may cause enormous disasters during their paths due to their significant heights and velocities.
In this study, the dam-break flows are examined by performing experimental tests, which include dam-break surges on both a horizontal bed and an inclined slope of 6 o . Five different dam heights was arranged, and the pressure distribution on the downstream vertical plate due to the impact of surges are analyzed. The approaching surge velocity and height of flow impact upon the vertical plate were analyzed via the high-speed camera. The maximum pressure on the vertical plate locates close to the channel bed, and the pressure distribution follows an exponentially decay curve instead of a linear profile. The maximum pressures on the tilt bed are about 1.2 to 1.5 times the values of the horizontal bed. The approaching velocity of the surge front is close 2√gH on the tilt bed. The forces acting on the vertical wall can be found by the integration of pressure distribution on the wall, which depicts the same pattern for both the horizontal bed and the tilt bed.

並列關鍵字

Dam-Break ； Surges ； Vertical wall ； Impact pressure

參考文獻

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