The Correlation Between Bed Roughness and Fluid Forces

床面粗糙度及水流作用力參數統一問題

周雙(SHUANG ZHOU) ； 張根廣(GENGUANG ZHANG) ； 王愉樂(YULE WANG)

《台灣水利》 67卷4期 (2019/12) Pp. 16-22

摘要

In order to study the incipient velocity of sediment particles in rough beds, an experimental device was designed to measure the distribution of the exposure angles of sediment particles. The obtained results showed that exposure angles conformed to Gaussian distribution. Based on the random mechanism of particle position and flow characteristics, an incipient probability of single particles concept, along with an equation for calculating this probability, are proposed. Additionally, an equation is derived to calculate incipient velocity based on incipient probability. Comparing the results obtained in this paper with experimental data, shows that the derived equations are of high practical importance. The mechanisms of coarse sediment incipient motion and transport are also investigated.

關鍵字

Exposure angle ； Incipient velocity ； Shear stress ； Roughness ； Fluid force

並列摘要

為研究粗糙河床上沙粒在高雷諾數時的作用力與起動流速問題，本文通過設計試驗裝置，測量了泥沙顆粒暴露角的分佈規律。結果表明，暴露角服從正態分佈。基於顆粒位置隨機性和水流脈動特性，提出了單顆粒起動概率的概念及其計算式，並推導出一個基於單顆粒起動概率理論的起動流速公式。本文公式與實測資料的對比結果表明，本文公式具有很好的適用性。本文研究對探索粗顆粒泥沙起動機理及推移質輸沙研究具有一定的意義。

並列關鍵字

暴露角度 ； 起動流速 ； 切應力 ； 粗糙度 ； 流體作用力