A novel particle tracking technique using a scanning laser setup tested via numerical experiment

We propose a novel robust 3D particle tracking technique based on a scanning laser setup. The present aim is to measure both Eulerian and Lagrangian statistics in densely-seeded turbulent flows with good spatial and temporal resolution, seeking to overcome inherent difficulties with line-of-sight based volumetric methods. To do this we have developed an effective triangulation virtually eliminating ghost particle reconstruction using images from only two cameras. A laser sheet is rapidly traversed ('scanned') across a measurement volume illuminating only a thin slice of the flow at a time. The triangulation process is further improved by using a fitted sheet number for individual particles to fix their true location along the scan direction (Knutsen et al., Exp. Fluids (2017) 58:145) instead of assuming the nominal sheet position where they are imaged. Following successful reconstruction of a time series of 3D particle fields, Lagrangian velocities and accelerations are calculated using particle tracking. The method is verified via numerical experiment using a DNS database. The present technique reconstructs a high fraction of known synthetic particle locations for densities above 0.05ppp. Comparison of a variety of statistics is undertaken to test the fidelity of the method.