将光场三维成像技术与实验流体力学相结合,实现单相机对空间三维瞬态流场(3D3C)的精确测量,为流体力学实验研究提供了一种全新的测试技术。详细介绍了具有自主知识产权的光场相机硬件系统、基于乘积代数重建技术(MART)的粒子光场图像重构算法以及基于光线追迹的数字光场图像合成算法。利用DNS数字合成图像以及低速射流实验图像,将所发展的光场单相机三维流场测试技术(Light Field Particle Image Velocimetry, LF-PIV)与目前最成熟的三维流场测试技术层析PIV(Tomographic Particle Image Velocimetry, Tomo-PIV)进行对比研究分析。实验结果表明LF_PIV技术完全能达到与Tomo—PIV同等量级的测量精度。
A novel single camera volumetric velocity measurement technique is presented, which utilizes the advanced light field imaging technology to capture 3D PIV tracer particle ima- ges. The framework of Light Field Particle Image Velocimetry (LF-PIV) includes an in-house high resolution light field camera, multiplicative algebraic reconstruction technique (MART) based light field particle image reconstruction method and a ray tracing based synthetic light field particle image generation platform. The LF-PIV technique is compared with Tomographic Particle Image Velocimetry (Tomo-PIV) by using both synthetic DNS jet flow images as well as water jet experimental images. Results show that LF-PIV is capable of reconstructing the instantaneous volumetric velocity field with the accuracy similar to that of Tomo-PIV.