###
工程科学与技术:2019,51(4):84-93
←前一篇   |   后一篇→
本文二维码信息
码上扫一扫!
明渠紊流脉动流速结构的PIV试验研究
(1.重庆交通大学 国家内河航道整治工程技术研究中心, 重庆 400074;2.重庆交通大学 水利水运工程教育部重点实验室, 重庆 400074)
PIV Experimental Study on Velocity Fluctuations of Turbulent Flow in Open Channel
(1.National Eng. Research Center for Inland Waterway Regulation, Chongqing Jiaotong Univ., Chongqing 400074, China;2.Key Lab. of Hydraulic and Waterway Eng. of the Ministry of Education, Chongqing Jiaotong Univ., Chongqing 400074, China)
摘要
图/表
参考文献
相似文献
本文已被:浏览 1524次   下载 718
投稿时间:2018-05-04    修订日期:2018-11-12
中文摘要: 明渠紊流的脉动流速结构对动量传递和能量耗散具有重要影响,基于光滑床面和加糙床面明渠紊流PIV流场测试资料,探讨了近壁区脉动流速的概率分布,分析了紊流事件概率的垂线分布特征,研究了雷诺应力和紊动能的象限分布及其与紊流事件概率的关系。结果表明:床面加糙会改变近壁脉动流速的概率分布和组织结构,加糙后纵向脉动流速概率分布变得尖陡且呈高狭峰,垂向脉动流速概率分布逐渐坦化并接近正态分布;光滑床面近壁区呈现清晰的高、低速条带结构,加糙后条带结构逐渐变得不规则甚至完全消失。床面加糙不会改变第2、4象限紊流事件的主导地位,但会改变其概率分布特征,加糙后第2象限紊流事件概率在全水深范围内总体增大,第4象限紊流事件概率仅在内区明显增大,床面加糙对第2象限紊流事件概率的影响范围大于第4象限,加糙后第2象限紊流事件的主导地位相对增强,第2、4象限紊流事件概率差异减小,紊流各向异性减弱。无论对于光滑床面还是加糙床面明渠紊流,第2、4象限的雷诺应力及紊动能总体大于第1、3象限,尤以第2象限最大,该象限紊动能可占总紊动能的39.3%;床面加糙后,第2、4象限的雷诺应力及紊动能绝对值均增大,雷诺应力在内区增幅尤为明显,紊动能在内、外区增幅较为接近;同时,第2、4象限的紊流事件概率、雷诺应力和紊动能变化具有较强的关联性。
Abstract:The fluctuating velocity structure of open channel turbulence has a significant influence on the momentum transfer and energy dissipation. Based on the instantaneous velocity data obtained by Particle Image Velocimetry (PIV) measurements in longitudinal sections for open-channel flows over smooth and rough beds, the probability distribution of the fluctuating velocity in the inner region was discussed. The vertical distribution characteristics of the probability of turbulence events (PTE) were analyzed, and the quadrant distribution of Reynolds stress (RS) and turbulent kinetic energy (TKE), as well as the relationship between RS, TKE and PTE were studied. The results showed that after bed roughness increased, the probability distribution and organization structure of the fluctuating velocity in the inner region would change. While the probability distribution of longitudinal fluctuating velocity became sharp and presented a high narrow peak, the probability distribution of vertical fluctuating velocity gradually flattened and came close to normal distribution. Meanwhile, the strip structure of the longitudinal fluctuating velocity clearly exhibited in the inner region of the smooth bed gradually became irregular or even disappeared. The predominance of turbulence events of the 2nd quadrant and the 4th quadrant would not change with bed roughness, but the distribution characteristics of PTE would vary. When bed roughness increased, PTE of the 2nd quadrant increased in general along the total water depth, while PTE of the 4th quadrant increased only in the inner region. The bed roughness had a greater impact on the 2nd quadrant turbulence event than the 4th quadrant turbulence event. Furthermore, the predominance of the 2nd quadrant turbulence events were relatively enhanced, while the difference of PTE between the 2nd quadrant and the 4th quadrant were reduced, and the turbulence anisotropy decreased. For open channel flow with smooth bed or rough bed, the RS and TKE of the 2nd, 4th quadrant were larger than that of the 1st, 3rd quadrant, especially the values of the 2nd quadrant were at their maximum, and the quadrant TKE could account for 39.3% of the total TKE. With the increase of bed roughness, the absolute values of RS and TKE of the 2nd, 4th quadrant were increased, the increase of RS in the inner region was particularly obvious, and the increase of TKE in the inner and outer regions was close. At the same time, the change of PTE, RS and TKE in the 2nd, 4th quadrant had strong relevance.
文章编号:201800495     中图分类号:TV131.2    文献标志码:
基金项目:国家自然科学基金项目(51509026);重庆市基础科学与前沿技术研究项目(cstc2017jcyjAX0278);湖南省交通科技项目(201830)
作者简介:钟亮(1980-),男,副教授,博士.研究方向:水力学及河流动力学.E-mail:zlcqjtu@163.com
引用文本:
钟亮,姜彤,张建梅,刘珺洁.明渠紊流脉动流速结构的PIV试验研究[J].工程科学与技术,2019,51(4):84-93.
ZHONG Liang,JIANG Tong,ZHANG Jianmei,LIU Junjie.PIV Experimental Study on Velocity Fluctuations of Turbulent Flow in Open Channel[J].Advanced Engineering Sciences,2019,51(4):84-93.