Application of POD Techniques to the Far Jet

项目摘要 利用本征正交分解（POD）技术对轴对称远喷流的动力学特性进行了实验研究。 总体目标是更好地了解远喷流的结构，以及近喷流预示其演变的程度。 该实验有两个具体目标： * 首先，POD技术将被应用到广泛的测量的速度互谱，以确定描述远射流的本征函数。 * 其次，确定的特征函数将被用来重建瞬时流量，空间和时间，在整体或部分。 调查将使用两个独特的实验装置：一个138热线探头早期开发的研究射流混合层;其他的飞行阵列的15热线，其间距的变化与下游距离射流出口。 这些技术将与已知的远喷流的单点和两点相似性特性结合使用，以确定包含流动的POD本征函数的空间和时间演变（包括它们的流向依赖性）。

PROJECT SUMMARY The dynamics of the fully-developed axisymmetric far jet using Proper Orthogonal Decomposition (POD) techniques will be investigated experimentally. The overall goal is to obtain a better understanding of the structure of the far jet, and the degree to which its evolution is foreshadowed by the near jet. The experiment has two specific objective: * First, POD techniques will be applied to extensive measurements of the velocity cross-spectra in order to determine the eigenfunctions describing the far jet. * Second, the eigenfunctions determined will be used to reconstruct the instantaneous flow, both spatially and temporally, in whole or in part. The investigation will use two unique experimental apparatus: one a 138 hot-wire probe developed earlier to study the jet mixing layer; the other a flying array of 15 hot-wire, the spacing of which changes with downstream distance from the jet exit. These techniques will be used in conjunction the known one- and two-point similarity properties of the far jet to determine the spatial and temporal evolution of the POD eigenfunction which comprise the flow (including their streamwise dependence)