ENDGAME - Laboratory Experiment 2024-03-21 Exp. 017 - High Speed Camera data

Shock-tube experiments in combination with high speed Schlieren shadow photography. The shocktube setup consists of a high-pressure reservoir connected with a cylindrical tube through a diaphragm pulse valve which allows a fast release of pressurized gas into the ambient pressure tube. The high-pressure reservoir is filled with compressed air at a given overpressure with respect to ambient pressure (up to 8 bar). The pipe was either empty (i.e. with air at ambient conditions) or filled with a given amount of small particles. We adopted a pipe with an inner diameter of 4 cm (outer diameter 5 cm) and 80 cm long. The volume of pressurized gas injected into the pipe was ~3000 cm3. In some cases a pressure sensor has been placed at the vent of the conduit to record pressure variations during the experiment. Images from the high speed camera were collected at a frame rate of 30000 fps. When the valve is open, a jet flow is produced, with shock and acoustic waves propagating in the atmosphere, which become visible due to the high speed Schlieren shadow photography.本数据集基于激波管实验结合高速纹影阴影摄影（Schlieren shadow photography）技术构建。 激波管装置由高压储腔与圆柱形管道通过隔膜脉冲阀连接组成，该阀门可实现加压气体向常压管道的快速释放。高压储腔填充的压缩空气相对于环境压力存在指定过压，最高可达8巴。试验所用管道可处于空置状态（即内部为环境条件下的空气），或填充指定量的细小颗粒。本次实验采用的管道内径为4厘米（外径5厘米），长度为80厘米，注入管道的加压气体体积约为3000立方厘米。部分实验中，会在管道排气口处安置压力传感器，以记录实验过程中的压力变化。高速相机以30000帧每秒的帧率采集图像，所获影像将被统一收集。 当阀门开启时，会产生射流流场，伴随激波及声波在大气中传播，此类现象可通过高速纹影阴影摄影技术清晰显现。