An experimental study of density-stratified gravity currents

• Main Authors: Cheng-Xi Yang, 楊承羲
• Other Authors: 許中杰
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/e4psm4

碩士 === 淡江大學 === 水資源及環境工程學系碩士班 === 104 === 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.