Particle-based flow visualization has long been practiced in flow diagnostics to gain in- sights into the fluid physics. Ludwig Prandtl’s water tunnel experiments of aerofoils are well-known to this day (see Prandtl (1936) and Willert & Kompenhans (2010)). Due to their huge prospects, particle imaging methods have been subject to extensive research, in order to enhance the methods from pure qualitative diagnostics to comprehensive quantitative flow analysis tools. Today, particle imaging techniques along with numeri- cal techniques are the key technologies for capturing three-dimensional (3D) flow fields and adjacent quantities. However, the required multi-camera set-ups are cumbersome, complex, and very costly and therefore limit the applicability. It is the purpose of this research to simplify particle-based 3D flow measurement techniques such that the range of applications can be broadened. A special attention is drawn to challenging measurement environments, with difficult optical access, vibrations, contamination, fluctuating seeding densities, and limited space for equipment.
To address the aforementioned requirements, the astigmatism particle tracking ve- locimetry (APTV) technique, well-established in microfluidics, was developed further, to meet the challenges of macroscopic flow measurements. The APTV method targets ap- plications in compressor, turbine, combustion, and engine research, as well as volumetric flow velocimetry in wind tunnel facilities with high mass flow rates.
Furthermore, the three-dimensional particle tracking velocimetry (3D-PTV) approach was refined to meet the specific challenges, which occur in double-pulse systems in a stereoscopic imaging set-up. For densely seeded flows, a combined tomographic 3D-PTV processing approach is introduced targeting at the measurement of complex flow fields with strong velocity gradients, while providing a high spatial resolution without requiring a time-series of recordings.
All the mentioned measurement technique developments are based on robust process- ing procedures and are therefore suitable for flow velocimetry in industrial environments.
Fakultät für Luft- und Raumfahrttechnik
LRT 7 - Institut für Strömungsmechanik und Aerodynamik