Flow past a swirler grid - PIV data from wind tunnel at Re 1.3 × 10^4 and 2.7 × 10^4

Particle Image Velocimetry (PIV) measurement of flow past a swirler grid.

This grid is designed to produce a regular system of clock-wise and anti-clock-wise vortices, which alternate in a same way as black and white squares on a chessboard. These longitudinal vortices are relatively stable and they play as a energy source at larger distances past the grid. Therefore, the maximum of turbulent kinetic energy (TKE) lies in the distance of ~ 10 × M (the mesh parameter).

- File "MeasuredPlanes.png" for general overview. The PIV is in Stereo configuration (so called 2D 3C).

- File "SwirlerGrid.scad" is the geometry (CAD), to open and modify that file, You will need open-source program OpenSCAD, https://openscad.org/. The geometry is described in more details in a function sample: https://www.kke.zcu.cz/cs/Research/function_samples (in Czech language)

- File "StereoPIV.zip" contains the measured data. They are organized in folders named e.g. "t05msX02", where "t05ms" means wind tunnel velocity of 5 m/s and "X02M" signifies the stream-wise distance in multiplies of M. Each such folder contains about 500 individual snapshots in ".csv" files, which are exported from Dantec Dynamic Studio. The data start at line no. 10. The column description is in line no. 9, velocity data are in columns 5 - 7, where 5th column (headed "U") represents the velocity in horizontal direction, i.e. y-axis in Figure "MeasuredPlanes.png"; 6th column (headed "V") is vertical z-velocity and 7th column (headed "W") is the stream-wise x-component.

颗粒图像测速法（PIV）对绕流旋流栅的测量。该栅格设计用于产生规则的顺时针和逆时针涡流系统，其交替方式与棋盘上的黑白格子相似。这些纵向涡流相对稳定，并在栅格后方较大距离处充当能量来源。因此，湍流动能（TKE）的最大值位于约10倍于M（网格参数）的距离处。

- 文件“MeasuredPlanes.png”提供了总体概览。PIV配置为立体配置（所谓2D 3C）。

- 文件“SwirlerGrid.scad”包含几何形状（CAD），要打开和修改该文件，您需要开源程序OpenSCAD，https://openscad.org/。几何形状的详细信息在函数示例中有更详细的描述：https://www.kke.zcu.cz/cs/Research/function_samples（使用捷克语）。

- 文件“StereoPIV.zip”包含测量数据。它们组织在名为例如“t05msX02”的文件夹中，其中“t05ms”表示风洞速度为5米/秒，“X02M”表示M的倍数的流向距离。每个这样的文件夹包含约500个单独的快照，以“.csv”文件形式导出，来自Dantec Dynamic Studio。数据从第10行开始，第9行描述列，速度数据位于第5至7列，其中第5列（标题为“U”）表示水平方向的速度，即图“MeasuredPlanes.png”中的y轴；第6列（标题为“V”）是垂直z轴速度，第7列（标题为“W”）是流向x轴分量。