Particle Image Velocimetry (PIV) measurement data for backward facing step flows with and without periodic perturbations

Flow fields downstream of a backward-facing step with a Reynolds number (UH/\nu) of 9630 were measured using a 2D2C PIV system. Freestream velocity is U=5.7m/s, H=0.025m. Flow was also perturbed using a synthetic jet actuator deployed at the separation point with a range of perturbation frequencies (St= 0.04 to 0.39) and amplitudes (u_A/U= 0.3 to 0.9) . A total of 2000 image pairs were acquired at a rate of 50 Hz for the unperturbed flow, 47 Hz for the flow perturbed at 70 Hz and 49 Hz for other perturbed flow. In this data set, there are a total of 37 data files saved in Matlab2013 MAT format. Files with a name 'f(a)c(b)Vec1.mat' have a size of 3280(spatial locations)*2000(number of snapshots)*2(two velocity components). Unit is m/s. Here in the file name, a=[0:1:9], 0:unperturbed flow, 1:perturbed at 10Hz, 2:20Hz, 3:30Hz, 4:40Hz, 5:50Hz, 6:60Hz, 7:70Hz, 7:70Hz, 8:80Hz, 9:90Hz; corresponding to St=fH/U=[0 0.0439 0.0877 0.1316 0.1754 0.2193 0.2632 0.3070 0.3509 0.3947]; b=[1:1:4], corresponding to perturbation amplitude of u_A/U=[0.3 0.5 0.7 0.9]. The file 'X.mat' and 'Y.mat' is the stream-wise and vertical position respectively. Both files have a size of 3280 and normalized using step height, H. More details about the experiment were described in Li, Z.Y., Guo, S., Bai, H.L. & Gao, N. 2019 Combined flow and heat transfer measurements of backward-facing step flows under periodic perturbation. Int J Heat Mass Trans 130, 240–251, 10.1016/j.ijheatmasstransfer.2018.10.077. I am available at [e-mail], or a permanent email [e-mail]采用二维二分量粒子图像测速（2D2C PIV, two-dimensional two-component particle image velocimetry）系统，对雷诺数（Re=UH/ν）为9630的后向台阶下游流场开展了测量。 实验中来流速度U=5.7m/s，台阶高度H=0.025m。 实验同时在流动分离点处部署合成射流促动器，对来流施加周期性扰动，扰动频率范围对应斯特劳哈尔数St=0.04~0.39，扰动振幅范围为u_A/U=0.3~0.9。 针对未扰动流动工况，以50Hz的帧率共采集2000对图像；针对70Hz扰动的流动，采集帧率为47Hz；其余扰动工况的采集帧率为49Hz。 本数据集共包含37个Matlab2013格式的MAT文件。命名格式为`f(a)c(b)Vec1.mat`的文件，其数据维度为3280（空间位置数）×2000（瞬态快照数）×2（两个速度分量），速度单位为m/s。 文件名中参数a的取值范围为0~9（步长为1）：a=0对应未扰动流动，a=1对应10Hz扰动、a=2对应20Hz、a=3对应30Hz、a=4对应40Hz、a=5对应50Hz、a=6对应60Hz、a=7对应70Hz、再次标注a=7对应70Hz、a=8对应80Hz、a=9对应90Hz，其对应的斯特劳哈尔数St=fH/U依次为[0, 0.0439, 0.0877, 0.1316, 0.1754, 0.2193, 0.2632, 0.3070, 0.3509, 0.3947]；参数b的取值范围为1~4（步长为1），对应扰动振幅u_A/U分别为[0.3, 0.5, 0.7, 0.9]。 文件`X.mat`与`Y.mat`分别存储流向与垂向的空间位置坐标，二者的数据维度均为3280，且已通过台阶高度H完成归一化处理。 本实验的详细细节可参见文献：Li Z Y, Guo S, Bai H L, Gao N. Combined flow and heat transfer measurements of backward-facing step flows under periodic perturbation[J]. International Journal of Heat and Mass Transfer, 2019, 130: 240-251, DOI: 10.1016/j.ijheatmasstransfer.2018.10.077。 联系方式：[e-mail]，永久备用邮箱：[e-mail]。