# 3D-Flow Measurement by Stereo Imaging

 Title 3D-Flow Measurement by Stereo Imaging Publication Type PhD Thesis Year of Publication 2000 Authors Engelmann, D University IWR, Fakultät für Physik und Astronomie, Univ.\ Heidelberg Abstract A new method to record three-dimensional liquid flow fields by using Particle Tracking Velocimetry' is presented. It is based on a two-dimensional Particle Tracking Velocimetry method. It was extended to the third space dimension in order to include the complete physical space. This procedure allows to determine the Lagrange-flow field and to calculate from it the Euler-velocity flow field obtained from many other flow measuring techniques. A calibration method was developed for the wind-wave-flume which allows a high resolution in space. The stereo camera setup and the experimental setup were optimized for the liquid flow measurements. For the first time a liquid prism and a Scheimpflug-camera geometry was used. Numerical calculations using the finite element method demonstrate the complexity of the problem of dealing with free surfaces with wind-induced shear forces as a boundary condition. They show clearly that experimental studies are indispensable for describing phenomena such as bursts' (descending of liquid elements from close to the surface into deeper layers). Flow measurements were performed in a newly constructed wind-wave-flume (AEOLOTRON) and in a smaller predecessor by using the newly developed imaging methods. In this way the flow fields of wind driven water waves could be characterized by the velocity field and the `turbulence' conditions. URL http://www.ub.uni-heidelberg.de/archiv/1070 Citation Key engelmann2000a