Three-dimensional particle tracking velocimetry for turbulence applications

Three-dimensional particle tracking velocimetry (3D-PTV) is a flow measure- ment technique that tracks the Lagrangian paths of a set of particles using photogrammetric principles. This technique allows to investigate complex fluid flows by measuring velocity and acceleration along particle trajectories. Implementing and optimizing the technique is, however, a somewhat di - cult task involving accurate optical set-up, volumetric illumination, precise calibration and rigorous post-processing. This thesis explains thorough guidelines to accomplish an optimal system set-up by discussing the hardware configuration, software operation, and post processing methods. First, this paper describes the system background for an e cient experimental set-up, such as the required camera specification, an accurate calibration method, an appropriate type of tracer particles and the illumination source. Then, the detailed usage of the 3D-PTV software, including the compilation and operation, with a description of file structures are discussed. To further utilize the output data, post-processing methods developed by Dr.Alex Liberzon, Dr.Beat Luthi and the author, which in- terpret the data both in Eulerian and Lagrangian frames, are explained. A circular jet flow is analyzed as demonstration of the technique