Laser Doppler Anemometry Dataset of Water Flow Downstream of a Venturi Nozzle at Fully Developed and Disturbed Inlet Flow Conditions.

This dataset contains velocity measurements in water collected with two laser Doppler anemometry probes downstream of a Venturi nozzle. The measuring volume size is 0.92 mm (along x-axis) and 0.06 mm (y-axis and z-axis). Measurements were carried out at four bulk Reynolds numbers between 50.000 and 945.000, at temperatures of 20 °C and 60 °C and at an abs. pressure of 2.5 bar. No positional corrections have been applied to the present dataset. Besides results for a fully developed upstream velocity profile (undisturbed), an asymmetric swirl disturbance generator was installed upstream of the Venturi nozzle and the measurement regime was repeated (disturbed). Detailed information about the experimental setup and procedures are available at DOI:10.1016/j.flowmeasinst.2020.101756. Describtion of the data structure: individual_burst_data: Filenames indicate in that order, separated by "_": - the upstream flow condition ("undist": fully developed pipe flow, "dist": asymmetric swirl disturbance generator 6D upstream of the optical access) - Reynolds-number in the upstream DN 150 pipe (e.g. "Re50k": Re = 50000) - Fluid temperature (e.g. "60C": T = 60 °C) - Number of the individual measurement out of three repeat measurements each (e.g. "1": First of three repeat measurements) - Description of the measurement system used (e.g. "ch1": System 1 was used for measurement) Each file contains one individual valid LDA burst event per row with four columns: x / mm - Horizontal position of the measuring volume center inside a 2-dimensional coordinate system that is perpendicular to the flow and with point of origin at the pipe axis. y / mm - Vertical position of the measuring volume center inside a 2-dimensional coordinate system that is perpendicular to the flow and with point of origin at the pipe axis. t / s - Relative time since start of the point-wise LDA measurement consisting of a number of individual LDA bursts. v / m/s - stream-wise particle velocity of this individual LDA burst. LDA bursts were collected at 300 points distributed all over the cross-sectional area of the glass pipe. due to limitations in software data handling, the resolution of the relative burst event time is limited to 1 millisecond. As a result, coincidental time stamps are occuring. Likewise, reset of the relative time appears sometimes. mean_velocities_data: Filenames follow the same scheme as for the individual burst data. Each file contains one row for each of the 300 measurement positions. x / mm - See above. y / mm - See above. v_mean / m/s - Average velocity of the LDA burst ensemble from the associated individual_burst_data-file. Averaging was carried out by inverse velocity weighting. Additionally, velocities were interpolated from nearby points if less than 10 bursts were recorded. Tu / % - Relative turbulence intensity. One standard deviation of the LDA burst velocity distribution divided by the arithm. mean velocity.本数据集包含文丘里喷嘴（Venturi nozzle）下游的两台激光多普勒测速仪（Laser Doppler Anemometry, LDA）探头采集的水流速度测量数据。测量体尺寸为：沿x轴0.92 mm，y轴与z轴均为0.06 mm。本次测量共设置四种总体雷诺数工况（范围50000至945000），流体温度分别为20℃与60℃，绝对压力为2.5 bar，且未对本数据集进行位置校正。 除包含上游流速剖面完全发展（未受扰动）的测量结果外，研究人员还在文丘里喷嘴上游安装了非对称旋流扰动发生器，并重复了全部测量工况（受扰动工况）。实验装置与测试流程的详细信息可参考DOI:10.1016/j.flowmeasinst.2020.101756。 数据结构说明如下： individual_burst_data：文件名按以下顺序以下划线分隔各字段： - 上游流动工况："undist"代表完全发展的管流，"dist"代表在光学入口上游6D位置安装非对称旋流扰动发生器 - 上游DN150管道内的雷诺数（例如"Re50k"表示Re=50000） - 流体温度（例如"60C"表示T=60℃） - 三次重复测量中的第几次测量（例如"1"代表三次重复测量中的第一次） - 所用测量系统的标识（例如"ch1"代表使用系统1完成本次测量） 每个文件的每行对应一个有效的LDA爆发事件，包含四列数据： - x / mm：测量体中心在以管道轴线为原点、垂直于流动方向的二维坐标系中的水平位置 - y / mm：测量体中心在上述二维坐标系中的垂直位置 - t / s：单点逐点LDA测量启动后的相对时间，单次测量包含若干独立LDA爆发事件 - v / m/s：该独立LDA爆发事件的流向粒子速度 LDA爆发事件在玻璃管道整个横截面上的300个测量点处采集。受限于软件数据处理能力，相对爆发事件时间的分辨率被限定为1毫秒，因此会出现重合的时间戳，且偶尔会发生相对时间重置的情况。 mean_velocities_data：文件名格式与individual_burst_data完全一致。每个文件包含300个测量位置各一行的统计数据，各列说明如下： - x / mm、y / mm：含义同上 - v_mean / m/s：对应individual_burst_data文件中LDA爆发事件集合的平均速度，采用速度倒数加权法完成平均计算。若某测点记录的爆发事件少于10次，则通过邻近测点插值得到该点速度值 - Tu / %：相对湍流强度，即LDA爆发速度分布的一个标准差除以算术平均速度。