Three-dimensional Lagrangian statistics of a turbulent free-shear jet

A fundamental study of a free-shear jet is performed to investigate the highly anisotropic and inhomogeneous flow field through Lagrangian statistics. Experiments were conducted within a Lagrangian Exploration Module, an icosahedron apparatus, to facilitate optical access of three high speed cameras. This enables the generation of 3D particle trajectories by implementing stereoscopic particle tracking velocimetry and results in three component tracks of position, velocity and acceleration of the tracer particles within the vertically-oriented jet. The total measurement volume is 80 x 80 x 200 mm$^3$, which includes over 50 nozzle diameters downstream, where the jet becomes self-similar. Lagrangian statistical analysis is performed to identify intermittent behavior at the centerline of the jet and at the turbulent/non-turbulent interface. Further, the applicability of Taylor's frozen flow hypothesis is investigated.