逆壁射流中射流剪切层内湍流结构特性的实验研究  

EXPERIMENTAL STUDY ON THE TURUBLENTCE STRUCTURE CHARACTERISES OF THE JET SHEAR LAYER IN A COUNTERFLOWING WALL JET

作　　者：刘宇陆 王宇泽[3] 李家骅 陶亦舟 邱翔 Liu Yulu;Wang Yuze;Li Jiahua;Tao Yizhou;Qiu Xiang(School of Science,Shanghai Institute of Technology,Shanghai 201418,China;Shanghai Institute of Applied Mathematics and Mechanics,School of Mechanics and Engineering Science,Shanghai University,Shanghai 200072,China;School of Mechanical Engineering,Shanghai Institute of Technology,Shanghai 201418,China)

机构地区：[1]上海应用技术大学理学院,上海201418 [2]上海大学力学与工程科学学院,上海市应用数学和力学研究所,上海200072 [3]上海应用技术大学机械工程学院,上海201418

出　　处：《力学学报》2023年第4期814-823,共10页Chinese Journal of Theoretical and Applied Mechanics

基　　金：国家自然科学基金(12032016,91952102);上海市教育委员会曙光计划(18SG53)资助项目。

摘　　要：用粒子图像测速技术对逆壁射流全流场进行了实验测量,射流与主流的速度比为8.89,基于射流圆管内径的雷诺数为9127.主要关注射流剪切层内不同流向位置端流的统计特性变化,包括尺度特性和结构特性.对射流中心线上不同流向位置的脉动速度场统计分析发现:在x/D=30~43,受反馈机制影响,Q1和Q4事件占据主导地位.在驻点附近(x/D=43~50)的区域Q3事件为主导事件.对射流剪切层内湍流结构的平均空间尺度进行分析,在x/D=0~37总尺度向射流下游发展呈增长趋势,在x/D=37~46总尺度几乎不变,x/D=46~51总尺度向射流下游发展呈减小趋势.在x/D=35之前,参考点上游尺度与下游尺度近似.在x/D=35~41,参考点下游尺度大于上游尺度.在x/D=41~51,参考点下游尺度小于上游尺度.利用频域上的本征正交分解方法对端流结构进行了定量分析,发现模态能量集中在低频,流场中能量最大的模态频率为D/U_(j)=0.0005,出现在再循环区.频率为fD/U_(j)=0.0026的第一阶模态说明射流发生偏转时与主流相互作用产生了流结构,并且沿再循环区外围输运.高频结构的构型是类似的,均位于射流剪切层内,且频率越高,越接近射流出口,尺度越小。The experimental measurement of the flow field of counterflowing wall jet using the particle image velocimetry.The jet velocity ratio to the main flow velocity is 8.89,and the Reynolds number based on the jet pipe is 9127.This paper focuses on the statistical characteristics of turbulence at different streamwise positions in the jet shear layer,including scale characteristics and structural characteristics.Statistical analysis of the fluctuating velocity field at different streamwise direction positions on the jet centerline shows that:in the range of x/D=30~43,Q1 and Q4 events dominate due to the feedback mechanism.Q3 event is dominant in the region near the stagnation point(x/D=43~50).The spatial scale of the turbulent structure in the jet shear layer is analyzed.The total scale in the interval x/D=0~37 shows an increasing trend downstream,and it is almost unchanged in the interval x/D=37~46.The total scale in the interval x/D=46~51 tends to decrease downstream.In the interval x/D=0~35,the upstream scale of the reference point is similar to the downstream scale.In the interval x/D=35~41,the downstream scale of the reference point is larger than the upstream scale.In the interval x/D=41~51,the downstream scale of the reference point is smaller than the upstream scale.The spectral proper orthogonal decomposition is used to quantitatively analyzes the turbulent structure.It shows that the energy of the mode is concentrated in low frequency.The most energetic mode in the flow field has a frequency of fD/U_(j)=0.0005 and appears in the recirculation region.The first mode with a frequency equal to fD/U_(j)=0.0026 indicates that the turbulent structure is generated when the jet is deflected by the interaction with the main flow,and transported along the periphery of the recirculation region.The configurations of high-frequency structures are similar,all located in the jet shear layer,and the higher the frequency,the closer to the jet outlet,the smaller the scale.

关 键 词：逆壁射流 粒子图像测速技术 频域体征正交分解方法 湍流结构 射流剪切层 

分 类 号：O357.5[理学—流体力学]