生態農業:農業地景生態監測及復育【水保系陳樹群特聘教授】
論文篇名 英文:A Hooked-Collar for Bridge Piers Protection: Flow Fields and Scour
中文:勾式橋墩保護套環: 流場與淘刷機制
期刊名稱 Water
發表年份,卷數,起迄頁數 2018,1251,357~367
作者 Su-Chin Chen, Samkele Tfwala*, Tsung-Yuan Wu,  Hsun-Chuan Chan  and Hsien-Ter Chou
DOI 10.3390/w10091251
中文摘要 藉由室內實驗和數值模擬的方法開發一種新型態的橋墩保護鉤環。室內實驗以寬度為1.25b且高度為0.25b的鉤狀套環進行試驗,其中b為橋墩寬度。實驗中改變勾環在橋墩上的位置並與無勾環的橋墩進行比較來探討勾環對橋墩的保護效果。實驗結果顯示,雙勾環的結構(一個勾還放置於床面,另一勾環埋於底床0.25b處)能最有效的減緩底床淘刷。而在床面上0.25b處的勾環也能稍微減少淘刷的產生,並與無勾環的橋墩有像似的淘刷模式。此外,室內實驗與數值模擬的垂直流場剖面也顯示,最大的向下射流可被勾環顯著的減少,並降低周圍馬蹄形渦流的強度,且最大的紊流動能強度也會隨著勾環的安裝而降低。
英文摘要 A new type of collar, the hooked-collar, was studied through experiments and numerical methods. Tests were conducted using a hooked collar of a width of 1.25b and a height of 0.25b, where b is the bridge-pier width. The hooked-collar efficiency was evaluated by testing different hooked-collar placements within the bridge-pier, which were compared to the bridge-pier without any collar. A double hooked-collar configuration, one placed at the bed level and the other buried 0.25b, was the most efficient at reducing the scour hole. In other cases, a hooked-collar positioned 0.25b above the bed slightly reduced the scour hole and had similar scour patterns when compared to the pier without the hooked-collar. The flow fields along the vertical symmetrical plane in the experiments are also presented. Laboratory experiments and numerical tests show that maximal downflow is highly reduced along with a corresponding decrease in horseshoe vortex strength for the experiments with the hooked-collar, compared to cases without the hooked-collar. The flow fields reveal that the maximum turbulent kinetic energy decreases with the installation of the hooked-collar.