坝区局地天气环境下的挑流喷溅水滴的碰撞和并合机制研究

Flood discharge atomization of ski-jump jet is one of the key factors that affect normal operation of hydraulic structures and stability of the slope, which includes three processes: fog rain generation, fog rain movement and fog rain deposition. During these processes, collision and coalescence of the splashing water droplets of ski-jump jet and other complicate physical phenomenon have a strong influence over rainfall intensity. This project is about to study on the collision and coalescence process of the splashing water droplets of ski-jump jet, with some combination of theoretical analysis, numerical simulation and prototype observation data, much attention will be paid to study the criterions of splashing water droplets before and after the collision under the nonuniform physical field of local weather in dam area, build collision and coalescence model of the splashing water droplets of ski-jump jet, as well as research the mechanism that the nonuniform physical field impact on splashing water droplets. Kinematic and dynamic behaviors of splashing water droplets of ski-jump jet will be explored, the collision and coalescence mechanism of splashing water droplets will be elucidated. The conclusions of the project will improve the understanding of flood discharge atomization of jet overflow from the microphysical process perspective, as well as provide theoretic support for engineering practice.

挑流泄洪雾化是影响枢纽建筑物正常运行和两岸边坡稳定性的重要因素之一。它包括三个过程：雾雨的产生、雾雨的运动、以及雾雨在下垫面的沉积。过程中有复杂的物理现象，如挑流喷溅水滴的碰撞和并合，它对降雨强度有着重要影响。本项目拟对挑流喷溅水滴的碰并过程进行研究，以理论分析、数值模拟和原型观测资料相结合的方式，重点考虑坝区局地天气所形成的非均匀物理场条件下，研究喷溅水滴间发生碰撞和碰撞后效判别条件，建立挑流喷溅水滴的碰并模型，研究坝下游非均匀物理场对喷溅水滴碰并的影响机制。探索挑流喷溅水滴的运动学、动力学规律，阐明喷溅水滴的碰并机制，从微物理过程的角度提高对挑流泄洪雾化的认识，为工程实践提供理论支持。

挑流喷溅水滴的碰撞和并合是一个复杂的微物理过程，它对降雨强度有着重要的影响，其遵循什么样的物理机制，是泄洪雾化的关键问题之一。之前对这个问题研究较少，本项目基于挑流泄洪雾化是在坝区局地天气环境下发生的情形，采用高分辨率的中尺度数值天气模式，结合小尺度数值模式，研究了在坝区局地天气环境下，挑流喷溅水滴的碰撞和并合机制，以及泄洪雾化与局地天气环境的相互影响。. 项目优化了适宜河谷地形的WRF物理参数化方案，并提出了泄洪雾化对天气环境影响的松弛同化方法，以反映泄洪雾化对坝区局地气象要素的影响；建立了WRF/LES多尺度耦合模型，以及WRF/Nudging/CALMET中尺度同化诊断模型，并应用格子Boltzmann和光滑粒子流体动力学等方法，精细地解析了坝下游非均匀物理场；建立了挑流喷溅水滴的碰撞和并合模型，数值模拟了水滴碰撞情形，以及水滴碰撞之后的并合、反射分离和拉伸分离等3种结果，能够刻画水滴碰撞和并合特性；在坝区局地天气的环境下，针对自然雨雾、泄洪水雾扩散、高坝泄洪雾化对天气环境的影响，进行了数值模拟研究，揭示了泄洪雾化与局地气象场相互影响机制。从泄洪雾化微物理过程和坝区局地天气环境的角度，深化了对挑流泄洪雾化的认识，为研究泄洪雾化的物理机制，提供了新的手段和方法。. 项目取得了一些有特色的成果。发表的15篇论文，荣获省部级科技进步一等奖一项。