Jiang Naibo, Mance Jason G, Slipchenko Mikhail N, Felver Josef J, Stauffer Hans U, Yi Tongxun, Danehy Paul M, Roy Sukesh
Opt Lett. 2017 Jan 15;42(2):239-242. doi: 10.1364/OL.42.000239.
Picosecond-laser electronic-excitation tagging (PLEET), a seedless picosecond-laser-based velocimetry technique, is demonstrated in non-reactive flows at a repetition rate of 100 kHz with a 1064 nm, 100 ps burst-mode laser. The fluorescence lifetime of the PLEET signal was measured in nitrogen, and the laser heating effects were analyzed. PLEET experiments with a free jet of nitrogen show the ability to measure multi-point flow velocity fluctuations at a 100 kHz detection rate or higher. Both spectral and dynamic mode decomposition analyses of velocity on a Ma=0.8 free jet show two dominant Strouhal numbers around 0.24 and 0.48, respectively, well within the shear-layer flapping frequencies of the free jets. This technique increases the laser-tagging repetition rate for velocimetry to hundreds of kilohertz. PLEET is suitable for subsonic through supersonic laminar- and turbulent-flow velocity measurements.
皮秒激光电子激发标记（PLEET）是一种基于皮秒激光的无种子测速技术，在非反应流中，利用波长为1064nm、脉宽为100ps的脉冲模式激光器，以100kHz的重复频率进行了演示。在氮气中测量了PLEET信号的荧光寿命，并分析了激光加热效应。氮气自由射流的PLEET实验表明，该技术能够以100kHz或更高的检测速率测量多点流速波动。对马赫数为0.8的自由射流速度进行的光谱和动态模式分解分析表明，两个主要的斯特劳哈尔数分别约为0.24和0.48，完全在自由射流的剪切层拍频范围内。该技术将用于测速的激光标记重复频率提高到了数百千赫兹。PLEET适用于亚音速到超音速层流和湍流流速测量。
