Unsteady Behavior of Necklace Vortex Produced by a Square Plate Protrusion

• 作者: Hidemi Yamada Keita Toda Teruyoshi Sadahiro Tsukasa Haraoka
• 来源期刊: 流体动力学(英文)
• 学科: 医学
• 关键词: NECKLACE VORTEX UNSTEADY Flow SQUARE PLATE Visualization PIV Analysis
• 年，卷（期）: 2018,（1）
• 页码范围: 59-72
• 页数: 14页
• 分类号: R73

摘要

In this study, the unsteady behavior of necklace vortices formed in front of a square flat plate was experimentally investigated by flow visualization and PIV analysis by using a water channel. As a result, the necklace vortices started to oscillate when the Reynolds number increased beyond approximately 2000. Then, an amalgamation behavior of the necklace vortices took place when the Reynolds number increased beyond approximately 2650. Furthermore, in the same Reynolds number range, a breakaway behavior appeared when the relative height of the square plate was beyond approximately h/δ = 4.0. The features of the necklace vortices behaviors in the oscillation, amalgamation and breakaway states were explained by observing the time-series image of path lines and by analyzing the frequency of velocity fluctuation.