Investigation on Flow Characteristics and Entrainment for lnclined Thermals as well as the Front of lnclined Strating Plumes

倾斜热气流及倾斜层流羽锋的流动特性和夹带研究

• 批准号: 06650568
• 负责人: AKIYAMA Juichiro
• 金额: $ 1.22万
• 依托单位: Kyushu Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06650568/
• 关键词: Density Current; Gravity Current; Inclined Plume; Inclined Thermal; Flow Characteristics; Entrainment; Laboratory Experiment

Miscible conservative two-dimensional gravity currents traveling downslope, namely, inclined starting plumes and inclined thermals were investigated theoretically and experimentally.In theoretical study, integral models were formulated for inclined thermals and inclined starting plumes. The proposed models incorporate the maior physical principles involved. For a wide range of practical applications, respective model is capable of predicting such plume or thermal characteristics as flow thickness, velocity, and density with higher accuracy than any available models.In Experimental study, a series of extensive laboratory experiments for inclined thermals and inclined starting plumes were conducted to quantify a number of important flow characteristics, including the geometry, shape factors, spatial growth rates, front propagation speeds, and entrainment functions of the flows. It is found from the application of a large volume of present experimental data that these flow characteristics are at most functions of bottom slope angle rheta for the range of rheta=5-90ﾟ and, consequently, were quantified as functions of rheta. It is also found that, except front propagation speed, no significant differences are identified regarding the flow characteristics between inclined thermals and the front of inclined starting plumes for the range of bottom slope angle rheta=5-90ﾟ.It is also found theoretically and experimentally that the dependence of the front propagation speed U_f, flow thichness H_f, and mean buoyancy B_f on longitudinal distance x are U_f=constant with x, H_f-x, and B_f-x^<-1> in inclined thermals, whereas U_f-x^<-1/2>, H_f-x, B_f-x^<-2> in the front of inclined starting plumes.

从理论上和实验上研究了向下倾斜的混合保守二维重力流，即倾斜起始羽流和倾斜热羽流。在理论研究中，建立了倾斜热气流和倾斜起始羽流的积分模型。所提出的模型结合了所涉及的主要物理原理。对于广泛的实际应用，各个模型能够以比任何现有模型更高的精度来预测诸如流厚度、速度和密度等羽流或热特性。在实验研究中，针对倾斜热气流和倾斜气流进行了一系列广泛的实验室实验。对起始羽流进行了量化，以量化许多重要的流动特征，包括流动的几何形状、形状因子、空间增长率、前沿传播速度和夹带函数。对于 rheta=5-90° 的范围，这些流动特性最多是底部坡角 rheta 的函数，因此，被量化为 rheta 的函数。还发现，除了前沿传播速度外，没有发现显着差异。流量底坡角rheta=5~90°范围内倾斜热气流与倾斜起始羽流锋面之间的特征。理论和实验还发现锋面传播速度U_f、水流厚度H_f和平均浮力B_f之间的关系在倾斜热气流中，纵向距离 x 上的 U_f=x、H_f-x 和 B_f-x^<-1> 常数，而U_f-x^<-1/2>、H_f-x、B_f-x^<-2> 位于倾斜起始羽流的前面。

项目成果

秋山 壽一郎: "保存性2次元傾斜サーマルの流動特性の普遍定量化" 水工学論文集. 第40. 549-554 (1996)

Juichiro Akiyama：“保守二维梯度热流流动特性的通用量化”《水利工程学报》第 40 期。549-554（1996 年）。

Akiyama Juichiro: "Physical-Based Numerical Model of Inclined Starting Plumes" Journal of Hydraulic Engineering,ASCE. Vol.120. 1139-1158 (1994)

Akiyama Juichiro：“基于物理的倾斜启动羽流数值模型”水利工程学报，ASCE。

Naoto TOMIOKA,Shunichiro SAITO,Juchiro AKIYAMA,and Masaru URA: "Flow Characteristics of Conservative Inclined Thermals・・・Resistance Coeffcient and Virtual Origine" Proc.of Annual Congress of Western Division of JSCE. 180-181 (1996)

Naoto TOMIOKA、Shunichiro SAITO、Juchiro AKIYAMA 和 Masaru URA：“保守倾斜热气流的流动特性……阻力系数和虚拟起源”，JSCE 西部分会年会论文集 180-181 (1996)。

斎藤 俊一郎: "傾斜サーマルの流動特性に関する理論的研究" 土木学会第50回年次学術講演会概要集. 534-535 (1995)

斋藤俊一郎：《倾斜热气流流动特性的理论研究》日本土木工程学会第50届学术年会摘要534-535（1995）。

Takeshi MORITA,Sanit WONGSA,Juichiro AKIYAMA,and Masaru URA: "Theoretical Investigation on Inclined Thermals" Proc.of the 49th Annual Congress of JSCE. Part2. 470-471 (1994)

Takeshi MORITA、Sanit WONGSA、Juichiro AKIYAMA 和 Masaru URA：“倾斜热气流理论研究”，JSCE 第 49 届年会论文集。