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：Incipient motion of large wood in river channels considering log density and orientation
中文：河道中大型木材在不同密度及方向下的初始運動狀態
期刊名稱 Journal of Hydraulic Research
發表年份,卷數,起迄頁數 2019,
作者 Su-Chin Chen, Samkele S. Tfwala, Ci-Rong Wang, Yi-Ming Kuo & Yi-Chiung Chao
DOI 10.1080/00221686.2019.1625816
中文摘要 使用48種不同長度、直徑、密度的手工原木在水槽試驗中探討他們的初始運動條件。原木的方向會決定它的啟動型態：平行的原木以滑動會主，而傾斜和橫向的原木則以滾動為主。原木的方向、直徑以及底床粗糙度皆對原木的啟動深度有明顯的影響，其中平行流向的原木與橫向和傾斜的原木相比，需要更大的啟動深度。此外，密度比水大的原木其啟動會與浮力有極大的相關性，啟動初期會以漂浮移動，接著會沿河床向下游滑動或滾動。本研究結果在統計資料上也具有相當良好的擬合程度，且原木在不同粗糙程度的底床上會具有不同的懸浮閥值，在實際應用時應謹慎選用。
英文摘要 The incipient motion conditions of large wood were tested in flume experiments using 48 handmade cylindrical logs of different lengths, diameters and densities. Their orientation to flow determined the motion: parallel logs slid, while oblique or transverse logs rolled. Log orientation, channel bed roughness, and log diameter had significance influence on entrainment depth. The logs’ density strongly influenced motion for logs parallel to flow. Logs oriented parallel to flow needed large entrainment depth to entrain than similar logs oriented oblique or transverse. Logs denser than water had high correlation with buoyancy, suggesting initial movement by floating, followed by either sliding or rolling downstream along the bed. From the modelled datasets, our results guided by the goodness of fit demonstrate that the floatation thresholds taken from global datasets should be applied with caution under different bed roughness conditions.