负浮力射流在温度和盐度双分层环境流体中的输移机理和卷积特性研究

为了有效利用负浮力射流在多组分分层环境流体中的输移机理和卷积掺混特性于环境治理和工程技术应用中，了解和掌握其瞬时流动特征和内在规律是至关重要的。但目前这方面的研究工作却鲜于报道。由于此类流动涉及多尺度（层流、湍流和转捩流）和多组分（温度、盐度等），其三维瞬时输移机理和卷积掺混特性是十分复杂的。本项目综合利用目前处于研究前沿的同步PIV/PLIF实验、DNS和LES数值模拟以及标度分析等研究手段对处于各种流动状态下的负浮力射流在温度和盐度双分层共存环境流体中的非稳态三维流动行为进行深入研究，揭示其独特的输移机理和卷积掺混特性，探索温度和盐度分层度、温度和盐度的分子扩散率、雷诺数、弗罗德数等特性参数对负浮力射流在不同温度分层度和盐度分层度下的卷积、失稳、湍流形成、掺混过程等的影响，并建立相关的量化物理数学模型，为环境水力学、环境流体力学、湍流理论等提供新内容，为工程技术应用提供重要的技术数据。

It is essential to fully understand the transient behavior and intrinsic laws of fountains in multi-component-stratified ambient if we want to optimally use their transport mechanisms and entrainment characteristics in environmental improvement and industrial applications. Nevertheless, this understanding is currently lacking. The flows of fountains in multi-component-stratified ambient are multi-scale (laminar, turbulent, and transitional) and multi-component (temperature, salinity, etc.) so their transport mechanisms and entrainment characteristics are very complicated. In this project, we will comprehensively use the cutting-edge synchronized PIV/PLIF experimental facilities, DNS and LES numerical simulation techniques, and scaling analysis to carry out an in-depth investigation of the three-dimensional transient flow behavior of fountains in temperature-stratified and salinity-stratified ambient in various flow regimes. It will reveal the transport mechanisms and entrainment characteristics of fountains in temperature-stratified and salinity-stratified ambient and explore the effects of the temperature stratification, salinity stratification, diffusivities of temperature and salinity, the Reynolds number, the Froude numbers, etc., on the entrainment, instability, turbulence generation and mixing process in fountains. It is expected that this project will establish the scaling laws between the representative parameters of the entrainment and mixing of fountains temperature-stratified and salinity-stratified ambient and the governing parameters of the flows. The outcomes of this project will provide insightful new knowledge for environmental hydraulics, engineering hydraulics, environmental fluid mechanics, turbulence theory, etc., and important technological data for engineering applications of such fountain flows.