Velocity and density distributions of a high-speed and initial CO2 jet flow have been analyzed concurrently by a developed three-dimensional digital speckle tomography and a particle image velocimetry (PIV). Two high-speed cameras have been used for the tomography and one for the PIV since a shape of a nozzle for the jet flow is bilaterally symmetric and the starting flow is fast and unsteady. The speckle movements between no flow and CO2 jet flow have been obtained by a cross-correlation tracking method so that those distances can be transferred to deflection angles of laser rays for density gradients. The three-dimensional density fields for the high-speed CO2 jet flow have been reconstructed from the deflection angles by the real-time tomography method, and the two-dimensional velocity fields have been calculated by the PIV method concurrently and instantaneously.

中文翻译：

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高速二氧化碳流速度和密度分布的同步测量研究

已开发的三维数字散斑断层扫描和粒子图像测速 (PIV) 同时分析了高速和初始 CO2 射流的速度和密度分布。两台高速相机已用于断层扫描，一台用于 PIV，因为射流喷嘴的形状是双边对称的，并且起始流动速度快且不稳定。通过互相关跟踪方法获得了无流和 CO2 射流之间的散斑运动，以便这些距离可以转换为密度梯度的激光射线偏转角。通过实时层析成像方法从偏转角重建了高速 CO2 射流的三维密度场，