Technical Report Paper abstract bibtex
We propose a novel robust three-dimensional particle tracking technique based on a scanning laser setup. The method yields Lagrangian statistics in densely-seeded turbulent flows with good spatial and temporal resolution, overcoming some of the inherent difficulty with line-of-sight based volumetric methods. To do this we have developed an effective triangulation method greatly reducing ghost particle reconstruction using images from two cameras. A laser sheet is rapidly traversed ('scanned') across a measurement volume illuminating only a thin slice of the flow at a time. Particle images are taken at closely-spaced, overlapping nominal laser sheet locations giving multiple intensity recordings for each individual particle. The laser-sheet intensity varies as a Gaussian across its thickness, which is here exploited to deduce the particle's probable location along the scan direction to sub-sheet number resolution by fitting a similarly-Gaussian profile to its multiple intensity recordings. Following successful reconstruction of a time series of three-dimensional particle fields, particle tracks are formed from which all components of Lagrangian velocity and acceleration are calculated. The method is presently verified via synthetic experiment using a database born of direct numerical simulation, and is intended for high-Reynolds number experimental flows.