Shake-The-Box 3D particle tracking for two-pulse recordings

The Shake-The-Box (STB) three-dimensional Lagrangian Particle Tracking (LPT) technique introduced the concept of particle prediction in order to integrate the temporal domain into the particle reconstruction process based on Iterative Particle Reconstruction. Taking advantage of long time-resolved (TR) recording sequences, the STB technique is able to cope with high particle image densities while delivering the accurate measurement of the particles position, velocity and acceleration along individual tracks. The Multi-Pulse STB extended the range of applicability of the algorithm to high flow velocities, where time-resolved recordings cannot be attained due to the limitation frequency of the high-speed acquisition systems, by adopting multi-pulse systems (i.e. dual illumination and imaging setup). Nevertheless, dual-frame 3D acquisition systems, consisting in a dual-cavity laser and double-frame cameras, remain commonly used for many particle-image-based investigations in a wide range of flow velocities and applications. As a consequence, a 3D LPT approach capable of dealing with two-pulse recordings is of high interest for both the scientific community and industry. In the present study, a Two-Pulse Shake-The-Box approach (TP-STB) is proposed, based on the advanced IPR algorithm presented by Jahn et al. 2021, in combination with the iterative scheme of reconstruction and tracking introduced for the Multi-Pulse STB algorithm development. The performances of TP-STB are assessed by means of comparison with the results from the time-resolved STB algorithm (TR-STB) on synthetic data. Application to an experimental dataset of Rayleigh-Bénard-Convection proves the concept in real-life conditions.