Coaxial round water jet at velocity ratios close to unity, Part I: Mean and turbulent flow characteristics

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL International Journal of Heat and Fluid Flow Pub Date : 2025-03-01 Epub Date: 2024-12-07 DOI:10.1016/j.ijheatfluidflow.2024.109650

D. Hasin , A. Mitra , R. van Hout

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Abstract

In this paper, planar time-resolved particle image velocimetry measurements are reported in the near-field of a coaxial jet at velocity ratios,

r_{u}

= 0.66, 1.0 and 1.32. At each

r_{u}

, at least two different Reynolds numbers, Re, were investigated. Spatial distributions of mean velocities, Reynolds stresses, vorticity and swirling strength strongly depend on

r_{u}

. Re effects in the normalized, mean velocity distributions were mainly visible in the wake associated with the finite lip thickness. In addition, increased normalized Reynolds stresses were obtained at

x / D_{o} \approx

1.5 for the lowest Re at a given

r_{u}

. Farther downstream, Re effects became negligible as inner and outer jets merged. A comparison between different terms in the turbulent kinetic energy (TKE) budget showed that TKE is predominantly produced in the outer shear layer, while turbulent diffusion results in radial transport. Mean advection of TKE (a “sink” term) is mainly significant close to the nozzle exit.

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接近单位流速比的同轴圆形水射流，第1部分：平均和湍流特性

本文报道了在速度比ru = 0.66、1.0和1.32时，同轴射流近场的平面时间分辨粒子图像测速。在每次运行中，至少研究了两个不同的雷诺数Re。平均速度、雷诺应力、涡度和旋流强度的空间分布强烈依赖于转速。归一化平均速度分布中的Re效应主要在与有限唇厚相关的尾迹中可见。此外，当x/Do≈1.5时，在给定的转速下，最低的Re得到了增加的归一化雷诺应力。再往下游，随着内外喷流合并，Re效应变得可以忽略不计。湍流动能收支中不同项的比较表明，湍流动能主要产生于外剪切层，而湍流扩散则导致径向输运。TKE的平均平流（一个“下沉”项）主要在喷嘴出口附近显著。

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来源期刊

International Journal of Heat and Fluid Flow 工程技术-工程：机械

CiteScore

5.00

自引率

7.70%

发文量

131

审稿时长

33 days

期刊介绍： The International Journal of Heat and Fluid Flow welcomes high-quality original contributions on experimental, computational, and physical aspects of convective heat transfer and fluid dynamics relevant to engineering or the environment, including multiphase and microscale flows. Papers reporting the application of these disciplines to design and development, with emphasis on new technological fields, are also welcomed. Some of these new fields include microscale electronic and mechanical systems; medical and biological systems; and thermal and flow control in both the internal and external environment.