陡坡光滑渠流之試驗研究

本試驗係採用光纖雷射杜卜勒測速儀（Fiber-optic Laser Doppler Velocimetry，FLDV）進行陡坡光滑床面明渠流之流場特性研究。試驗寬深比介於3.79與11.36之間；光滑底床坡度分別為0.3％、1％及2％；福祿數（Froude number）為0.96至2.72；雷諾數（Reynolds number）涵蓋10^4與8×10^4之範圍。對於試驗所收集之資料，分為二維與三維流場討論，其中大部份試驗屬於超臨界流況（supercritical flow）。本文中主要比較壁定理（law of the wall）、速度欠損律（velocity defect law）以及1/7冪次定理（one-seventh power law）等速度分佈定理，以瞭解陡坡明渠流之水力特性。

關鍵字

陡坡明渠流；光纖雷射杜卜勒測速儀；壁定理；速度欠損律； 1/7冪次定理

並列摘要

A Fiber-optic Laser Doppler Velocimetry (FLDV) was adopted in this experimental study to investigate the characteristics of the steep open channel flow with a smooth boundary. In this study, the aspect ratio varied from 3.79 to 11.36, the Reynolds number varied from 10^4 to 8 x 10^4, and the channel bed slope of 0.3%, 1% and 2% were selected. Both two-dimensional and three-dimensional flow were discussed. The Froude number ranged from 0.96 to 2.72, and most of the experiments belonged to supercritical flow. The objectives of this research were to study the mean velocity profiles of the steep open channel flow. The measured velocity profiles were compared with the law of the wall, the velocity defect law and the one-seventh power law.

並列關鍵字

Steep open channel flow ； Fiber-optic Laser Doppler Velocimetry ； Law of the wall ； Velocity defect law ； One-seventh power law

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