Investigation of Turbulent Coherent Structures in the Separation and Reattachment of Flow behind a Swept Backward-Facing Step

后掠台阶后面流动分离和重新附着中的湍流相干结构研究

• 批准号: 20560154
• 负责人: YAMASHITA Shintaro
• 金额: $ 3.16万
• 依托单位: Gifu University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2008
• 资助国家: 日本
• 起止时间: 2008 至 2010
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-20560154/
• 关键词: 乱流

In the present study, the flow over a swept backward-facing step has been investigated experimentally and numerically. Measurements were made by single hot-wire and flying hot-wire (referred to as FHW) techniques. In order to confirm the applicability of the FHW in the spanwise direction, the standard turbulent boundary-layer was examined by comparing with a hot-wire rake. Mean and fluctuating velocity distributions were measured in the flow separated from a sharp edge, and compared with those in the turbulent boundary layer. The FHW was tried to capture the turbulent coherent structures in the spanwise direction. For two-dimensional backward-facing step flow, the relative step height to boundary layer thickness of an incoming flow were H/δ_0=0.5, 1.0 and 1.5. Mean and fluctuating velocity distributions for H/δ_0=0.5 and 1.0 were examined by a stationary hot-wire and flying hot-wire anemometer with I-type probe. Streamwise distributions of the forward-flow fraction, γ, near the wall were calculated, and then reattachment points of the separating flow were evaluated as a location of γ=50%. In the range of H/δ_0=0.5 to 1.5 in the present study, the reattachment length is almost constant.

本文对后掠后台阶的流动进行了实验和数值研究。通过单热线和飞热线（称为FHW）技术进行测量。为了证实FHW在展向方向的适用性，通过与热线耙比较来检查标准湍流边界层。测量了从锐缘分离的流动中的平均速度分布和脉动速度分布，并与湍流边界层中的速度分布进行了比较。FHW试图捕捉展向湍流相干结构。对于二维后向台阶流动，台阶高度与来流边界层厚度的相对关系为H/δ 0 =0.5，1.0和1.5。用固定式和飞行式I型热线风速仪测量了H/δ_0=0.5和1.0时的平均速度分布和脉动速度分布。计算了壁面附近前向流份额γ的流向分布，然后将分离流的再附着点估计为γ= 50%的位置。在H/δ_0=0.5 ~ 1.5的范围内，再附着长度几乎为常数。

项目成果

回転円筒上の層流境界層へのPade近似の応用

Pade 近似在旋转圆柱体上层流边界层的应用

• 发表时间: 2010
• 作者: 山下新太郎;受井嘉治;井上吉弘
• 通讯作者: 井上吉弘

低Re数における円形壁面噴流の可視化実験

低Re数环壁射流可视化实验

• 发表时间: 2010
• 作者: 澤貴行;井上吉弘;山下新太郎
• 通讯作者: 山下新太郎

Experimental Study on Turbulent Coherent Structures in a Separated Boundary-Layer from a Sharp Edge

锐边分离边界层中湍流相干结构的实验研究

• 发表时间: 2010
• 作者: S.Yamashita;Y.Inoue;K. Sasaki;T.Nagahama
• 通讯作者: T.Nagahama

A Comparative study on Near-field Flow Structures in a Circular Free Jet and a Square Free Jet

圆形自由射流与方形自由射流近场流动结构对比研究

• 发表时间: 2008
• 作者: Y. Inone;K. Koudo;S. Yamashita
• 通讯作者: S. Yamashita

回転円柱まわりの流れ場に関する研究(一様回転時の円柱近傍の流れ)

旋转圆柱体周围流场研究（匀速旋转时圆柱体附近的流动）

• 发表时间: 2010
• 作者: 青山健一;井上吉弘;山下新太郎
• 通讯作者: 山下新太郎