Development of particle imaging methods for near-wall flow measurements in air and generation of CFD validation data sets for aerodynamics

• Applicant: Dr.-Ing. Thomas Fuchs
• Subject Area: Fluid Mechanics
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 574766644

Particle imaging techniques are highly capable, versatile velocimetry approaches that are widely applied in fluid mechanics. In this project, it is the primary objective to advance particle imaging techniques for near-wall flow measurements. Specifically for applications in aerodynamics, following goals are pursued: (1) Adaption of the defocusing PTV, the stereoscopic 3D-PTV, and the parallax PTV technique to measure flows over curved surfaces. (2) Conduction of comprehensive uncertainty assessments of these techniques under realistic conditions. (3) Generation of dependable validation data sets for CFD developers in aerodynamics. Each of the three proposed techniques, defocusing PTV, stereoscopic 3D-PTV, and parallax PTV have their individual benefits, complementing each other. Thus, the optimal technique can be selected depending on the experimental boundary conditions, such as optical access, surface material, working distance. Together these techniques can cover a variety of measurement tasks in aerodynamics. Building up on the improvements of the proposed techniques, it is intended to perform near-wall flow measurements on the so-called "Speed Bump" model. The "Speed Bump" is a CFD validation experiment, featuring a separation region which is difficult to predict for numerical methods. With the near-wall velocimetry techniques it is intended to provide reliable flow information in the proximity of the bump surface. The data is going to include the wall-shear-stress values, that are derived from a linear fit of the flow profile in the viscous sub-layer. In aerodynamics, a precise knowledge of the wall-shear-stress is highly desired, since it allows for more accurate drag calculations. Continuous improvements of both experimental methods and CFD methods are key factors to enhancements in aerodynamic design processes.

• DFG Programme: Research Grants