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    Please use this identifier to cite or link to this item: http://tkuir.lib.tku.edu.tw:8080/dspace/handle/987654321/111512

    Title: 分層異重流的實驗研究
    Other Titles: An experimental study of density-stratified gravity currents
    Authors: 楊承羲;Yang, Cheng-Xi
    Contributors: 淡江大學水資源及環境工程學系碩士班
    Keywords: 異重流;分層;Gravity currents;stratification
    Date: 2016
    Issue Date: 2017-08-24 23:55:12 (UTC+8)
    Abstract: 本文探討分層異重流的實驗。為兩種有密度差異的分層流體流動進另一個密度比分層流體相對較小的背景流體中的實驗。主要目的在於透過理論解析以及實驗系統性的探討分層異重流於慣性區段的影響。於定量與定性分析過程中,了解分層異重流在運動中所產生的混合及分離的過程。於慣性區段的異重流運動型態將遵守3/2 指數關係,並且與密度比(rho∗) 以及重力比(B∗) 相關。透過觀察分層異重流於慣性區段之福祿數 (FI) 變化、rho∗與B∗之關聯性來了解流動型態的特性。首先從實驗之分析結果得知,當密度均勻之均質異重流體進入背景流體其慣性區段的FI值約為1.33,其值皆大於非均質之分層異重流的例子。當初始分層條件為弱分層情形時(0.5<rho∗<1),其分層異重流產生混合的現象也相當迅速;若初始分層條件為強分層情形時 (0<rho∗<0.5),其混合的現象則相對緩慢。於弱分層與強
    分層的情形之間,當重力比值較大時(B∗→1)會發生以上層流體為主導的形流動型態;若是重力比值較小時 (B∗→0) 會發生以下層流體為主導的形流動型態。藉由慣性區段的FI值、rho∗以及重力比B∗於幫助了解分層異重流的運動型態和特徵。
    This paper examines experiment of density-stratified gravity currents. There are two kinds of fluid of density-stratified difference penetrating into ambient fluid. The main objective focus on investigating the influence of density-stratification on the gravity currents is systematically explored in the inertial phase through the theoretical and experimental studies. The mixing and discrete processes are represented produced by density-stratified buoyancy source in qualitative and quantitative method. In the inertial phase of propagation, the flow pattern of gravity current follows the 3/2 power relationship related with the Froude number, density difference ratio (rho∗) and distribution of buoyancy (B∗). First, from the experimental results, the Froude number in the inertial phase has its maximum value at 1.33 as the density and buoyancy is homogeneous, always great than the values of non-homogeneous stratified fluid. When density-stratified gravity currents from a weakly stratified source (0.5<rho∗<1), the mixing between the two-layer fluids is quick; from the strongly stratified source (0<rho∗<0.5), the mixing between the two-layer fluid is generally slower. Between weakly and strongly stratified sources, the flow is controlled by the upper layer fluid when the distribution of buoyancy large (B∗→1) ; when the distribution of buoyancy few the flow is controlled by the lower layer fluid (B∗→0) . Since the Froude number, density difference ratio and distribution of buoyancy is helpful in offering possible explanations for observed features from density-stratified gravity currents.
    Appears in Collections:[水資源及環境工程學系暨研究所] 學位論文

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