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.

在本研究中，已经通过实验和数字研究了扫描向后的步骤的流动。通过单热线和飞行热线（称为FHW）技术进行测量。为了确认FHW在跨度方向上的适用性，通过与热线耙进行比较来检查标准的湍流边界层。在与尖锐边缘分离的流中测量了平均和波动的速度分布，并与湍流边界层中的速度分布进行了比较。 FHW试图捕获沿跨度方向捕获湍流相干结构。对于二维向后的步长，输入流的相对步高至边界层厚度为H/δ__0= 0.5、1.0和1.5。使用I-type探针的固定热线和飞行热线接线表检查了H/Δ_0= 0.5和1.0的平均速度分布和1.0。计算向前流动部分γ的流向分布在壁附近，然后将分离流的保留点评估为γ= 50％的位置。在本研究中，在H/δ_0= 0.5至1.5的范围内，保留长度几乎是恒定的。

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

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

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

後方ステップによるはく離流れの乱流組織構造に関する実験的研究

后向阶梯分离流湍流结构实验研究

• 发表时间: 2009
• 作者: 井上吉弘;長濱達也;山下新太郎
• 通讯作者: 山下新太郎