Separation Points on Cylinders in Oscillating Flow

这一持续研究项目的总体目标是增加对钝体随时间分离流的基本理解。利用现有的u型振荡流隧道和广泛的数据采集系统，通过使用浸泡在正弦振荡流中的光滑和粗糙圆柱体来获得准确的分离点数据。将使用四种方法来确定分离点作为时间和流动模式的函数：差压法、表面压力分布法、冲洗热膜表面传感器和染料注射法。这些数据将与先前研究过程中通过使用离散涡模型进行的数值预测进行比较。所提出的研究不仅将提供急需的关键比较，而且将有助于通过消除或减少一些假设来推广漩涡方法。实验数据和数值分析之间的相互作用将增强我们对实际关注的雷诺数下钝体随时间流动的基本理解。

The overall objective of this continuing research program is to add to the basic understanding of time-dependent separated flow about bluff bodies. Using an existing U-shaped oscillating flow tunnel and extensive data acquisition system, accurate separation point data will be obtained through the use of smooth and rough cylinders immersed in a sinusoidally oscillating flow. Four methods will be used to determine the separation points as a function of time and flow mode: Differential Pressure Method, Surface Pressure Distribution Method, Flush Hot Film Surface Sensors, and the Dye Injection Method. The data will be compared with those predicted numerically during the course of the prior investigation through the use of the discrete vortex model. The proposed investigation will not only provide the much needed critical comparison but will also help to generalize the vortex methods by removing or reducing some of the assumptions. The interplay between the experimental data and the numerical analysis will enhance our fundamental understanding of time-dependent flow about bluff bodies at Reynolds numbers of practical concern.