Research on the Vortex Structure in Rotating Cavity Flow by means of Simultaneous

旋转空腔流涡结构的同步研究

• 批准号: 09650182
• 负责人: YAMASHITA Shintaro
• 金额: $ 2.18万
• 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: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650182/
• 关键词: Cavity Flow; Three-Dimensional Flow; Separated Shear Layer; Vortex Structure; Spatio-Temporal Measurement; PIV; Ultrasonic Velocity Profile Monitor; 遠心力不安定

This research aims to clarify the vortex structure of the flow in a cavity formed peripherally on a cylinder rotating in a uniform axial stream. The aspect ratio, i.e., the ratio of the width of the cavity to the depth. was varied from 1 to 4. Experiments were carried out in a water tunnel, and measurements were made by using a PIV (Particle Imaging Velocimetry) and a UVP (Ultrasonic Velocity Profile Monitor). A progress of this research and main results obtained are as followings.1. The cylinder model was made, whose nose part was of streamline shape based on the axisymmetric potential flow. The cylinder was supported as a cantilever on its rear end and by fine wires on its front part.2. The soft ware for PIV measurements to analyze the images on the basis of cross-correlation method was developed, and it was refined as to measure accurately the velocity in the cavity which varied over wide range in its magnitude. Further the development of the soft ware for the simultaneous measureme … More nt with the PIV and UVP was undertaken, and the consultation was made for the tracer particles seeded in the water for this measurement. As a result we fixed to use simultaneously the fluorescent dye for the PIV and the hydrogen bubbles generated by the electrolysis of the water for the DVP.3. Following the above preliminary research, the experiment was made for the flow field in the cavity of its aspect ratio 1 and 4. First, the flow visualization with no rotation of the cylinder revealed that the cavity flow presented the vortex structure composed of a main vortex of the scale comparable to the cavity depth and of some secondary vortices as in two-dimensional cavity flow, and also that the shear layer separated at the upstream edge of the cavity oscillated and the position of reattachment point varied quasi-periodically.4. The vector map of the mean velocity and the contour map of the mean vorticity were obtained from the PIV measurement. They exhibited the magnitude and the configuration of the main vortex and the secondary vortices quantitatively. The spatio-temporal behavior of the separated shear layer was examined from the DVP measurement. The phenomenon of the spatio-temporal swaying of the shear layer was revealed, and the mean frequency of the oscillation and the space-time correlation of the fluctuating velocity in the shear layer were obtained.5. We proceed with more detailed measurements and data analyses, and will investigate the roll-up phenomenon of the shear layer, the clipping of the layer on the downstream edge of the cavity, the fluctuating vorticity distribution, and so on, in order to clarify the three-dimensional vortex structure in the axi-symmetric cavity. Less

本研究的目的是为了弄清圆柱体在均匀轴流中旋转时，圆柱体外围形成的空腔内流动的旋涡结构。纵横比，即空腔宽度与深度的比率。实验在水洞中进行，使用PIV(粒子成像测速仪)和UVP(超声速度剖面监测器)进行测量。本文的研究进展和取得的主要成果如下：1.根据轴对称势流理论，建立了圆柱体模型，鼻部为流线型。钢瓶的后端用悬臂支撑，前部用细金属丝支撑。开发了基于互相关法的PIV测量图像分析软件，并对其进行了改进，使之能够精确测量大范围变化的空腔内速度。同时测量…软件的进一步开发进行了更多的NT与PIV和UVP，并参考了示踪剂颗粒在水中播撒的测量。因此，我们决定同时使用用于PIV的荧光染料和用于DVP的电解水产生的氢气泡。在此基础上，对长径比为1和4的空腔内的流场进行了实验研究。首先，在不旋转圆柱体的情况下，空腔流动呈现出与二维空腔流动相同的由尺度与空腔深度相当的主涡和一些次涡组成的旋涡结构，空腔上游边缘分离的剪切层振荡，再附着点位置准周期变化。通过PIV测量得到了平均速度矢量图和平均涡量等值线图。它们定量地显示了主涡和次涡的大小和形状。通过DVP测量考察了分离剪切层的时空行为。揭示了剪切层的时空摆动现象，得到了剪切层内振动的平均频率和脉动速度的时空相关性。我们进行了更详细的测量和数据分析，并将对剪切层的卷曲现象、空腔下游边缘的剪切层、脉动涡量分布等进行研究，以阐明轴对称空腔中的三维涡旋结构。较少

项目成果

山 下 新 太 郎: "軸流中の細長回転円筒上の乱流境界層の実験(第3報)" 日本機械学会論文集B編. 64巻. 3234-3240 (1998)

Shintaro Yamashita：“轴流中细长旋转圆柱体上的湍流边界层实验（第 3 次报告）”日本机械工程师学会会刊，第 B 卷，第 64 卷，3234-3240（1998 年）

矢 野 治 久: "軸流中の回転円筒上乱流境界層のエネルギ収支とスペクトル" 日本流体力学会誌 「ながれ」. 16巻別冊. 149-150 (1997)

Osamu Yano：“轴流中旋转圆柱体上的湍流边界层的能量平衡和频谱”日本流体力学学会杂志“Nagare”第 16 卷，单独发行（1997 年）。

山下新太郎: "円筒上キャビティ内流れの非定常特性のPIV測定" 日本機械学会流体工学部門講演会. (発表予定). (1999)

Shintaro Yamashita：“圆柱腔内流动非稳态特性的PIV测量”日本机械工程师学会流体工程分部讲座（待发表）。

矢野治久: "軸流中の回転円筒上乱流境界層のエネルギ収支とスペクトル" 日本流体力学会誌「ながれ」. 16巻別冊. (1997)

Haruhisa Yano：“轴流中旋转圆柱体上的湍流边界层的能量平衡和谱”，日本流体力学学会期刊“Nagare”，第 16 卷（1997 年）。

Haruhisa YANO: "Coherent Structure of the Turbulent Boundary Layer on a Cylinder Rotating in an Axial Flow (in Japanese)" Proceedings of the 75th JSME Spring Annual Meeting. No.98-1 (III). 161-162 (1998)

Haruhisa YANO：“轴流旋转圆柱体上湍流边界层的相干结构（日语）”第 75 届 JSME 春季年会论文集。