空中水舌水力特性的数值模拟研究

Hydraulic Characteristics of Jet Flow Numerical Simulation Research

空中水舌的水力特性与下游雾化及冲刷密切相关,因此得到空中水舌形态、水舌扩散特性和断面流速分布等计算公式十分重要。对空中水舌进行三维数值模拟,在等宽出口形式下,通过改变来流断面水流弗劳德数Fr,重点研究了水舌紊动扩散规律、断面流速分布规律等,并采用理论推导法得到沿程断面平均流速的计算公式。研究结果表明:Fr值越大,水流沿程横向扩散越强烈;水舌横向扩散率初始较大,随着射距的增加,扩散率逐渐减小;水舌纵向厚度同射距近似呈直线关系;断面流速分布服从正态分布,且不同射距处的无量纲流速分布曲线可用同一条曲线表示。

Hydraulic characteristics of water jet flow are closely related to atomization and scour of prototype. This means,the formulas which including form,the diffusion of qualities and velocity distribution of sections are important. This article simulated flow jet with the method of 3D numerical simulation and focused on turbulent diffusion laws and velocity distribution of sections by changing Froude number. Meanwhile theoretical formula calculation was adopted to get mean velocity formula. The results show that with the bigger Froude number,the more intense of transverse diffusion is,the greater the transverse diffusivity will be and gradually decreases with the distance to export increa-ses. The jet thickness is approximately linear to distance. The velocity distribution follows normal distribution. The results further enrich hy-draulic characteristics of water jet flow that can be used as a reference for design of engineering.