方案摘要
方案下载应用领域 | 其他 |
检测样本 | 其他 |
检测项目 | |
参考标准 | 暂无 |
Proper Orthogonal Decomposition (P.O.D.) is a technique used for analysis of vortex structures in a turbulent flow. In this study, complex shear flows are observed by P.I.V. measurements (Particle Image Velocimetry) of a large diameter ratio annular jet. The annular jet is an example of complex shear flow situations. Two axisymmetric shear layers, originating at the jet exit, one at the nozzle lip and the other at the centre body, eventually meet downstream or interact with each other. The main aim of this study is to observe and analyze the effects of active control using acoustic waves on an annular jet with a great diameter ratio (r= 0.91), in order to find a new way to reduce jet instabilities. This contribution discusses the application of Proper Orthogonal Decomposition to the P.I.V. (Particle Image Velocimetry) velocity fields of an annular jet and on a statistic of time resolved tomographic images of the initial zone of the annular jet. Acoustic waves are then applied on the annular jet with different frequencies (fundamental, first harmonic̷). Measurements are conducted with a Reynolds number ReDo=107800. The fluctuation frequency of the stagnation point is known for this Reynolds number. The Strouhal number corresponding to this frequency is StDo = 0.27. The P.O.D. analysis applied on a natural annular jet and an excited annular jet enables us to see the importance of the triggering of the acoustic wave with the stagnation point motion. An active control is therefore necessary to use acoustic excitation to reduce instabilities in the initial zone of these turbulent jets. Active control has already been used with round jets and has given promising results, but only a few studies have been conducted on annular jets in this field. This work will permit us essentially to have a better knowledge of annular jets and to meet manufacturers' needs.
在一个双稳湍流涡旋火焰中,对间歇性动态的时间-频率定位
Particle-laden Taylor-Couette流:高阶转变和径向局部波浪涡旋的证据
7根杆束的流体-结构相互作用:用实验数据对比数值模拟
汽车光学检测系统AIS
PT403型波长可调谐皮秒激光器
ANL系列高能量高重复频率DPSS纳秒激光器
APL4206 系列高能量皮秒激光放大器
UltraFlux FF/FT 5000 高能量可调谐飞秒激光器系统
UltraFlux FT300型波长可调谐飞秒激光器系统
Ekspla 超高功率激光器系统SYLOS 2A
LaVision PTUx 可编程时间控制单元
LaVision 用于粒子成像测速PIV的相机
LaVision StrainMaser 全场应变测试系统组件
LaVision 用于数字图像相关DIC的相机
LaVision StrainMaster 数字图像相关分析软件包
LaVision 标定板
LaVision StrainMaster 形变应变成像测量系统
LaVision StrainMaster DVC 体视全场应变测量系统
关注
拨打电话
留言咨询