3D PTV AND ITS APPLICATION ON LAGRANGIAN MOTION

Three-dimensional particle tracking velocimetry (3D PTV) is a flow mea surement technique for the determination of velocity vectors and traje ctories within a three-dimensional observation volume. This makes this technique suitable not only for Eulerian but also for Lagrangian inve stigation of flow phenomena, especially in the field of turbulence and turbulent diffusion. The principle and the application on open channe l flow of 3D PTV are briefly described in the first part of this paper . By decomposition of the velocity vectors velocity profiles and turbu lence intensities are derived and presented in the second part. Turbul ent energy dissipation, Kolmogorov length and time scales and Taylor m icro scales are computed from the measured data sets. In the Lagrangia n analysis pdf's of the Lagrangian acceleration, correlation coefficie nts and Taylor micro scales are determined. The individual determinati on of the particle positions and displacements allows finally the appl ication on the one and two particle approaches for turbulent diffusion from Taylor (1921), Richardson (1926) and Batchelor (1949, 1952).