Advancements in Large-Scale Volumetric PIV and PTV

Particle Image Velocimetry (PIV) is considered nowadays the state-of-the-art for non-intrusive and quantitative 3D velocity measurements. Its ability to measure the velocity field around complex geometries is a valuable tool that engineers can exploit for aerodynamic design optimization in various domains, such as aerospace, wind turbines and...

Wake and wind farm aerodynamics of vertical axis wind turbines

The development of offshore wind energy, especially the steps towards deep water and/or higher density wind farms, revives the prospects of vertical axis wind turbines (VAWTs). Because VAWTs may reduce the cost of floating structures, there is a potential to lower energy costs. However, VAWTs are often assumed to be less efficient and less...

Development of robotic volumetric PIV: with applications in sports aerodynamics

Particle image velocimetry (PIV) is the state of the art for quantitative, full-field, 3D flow diagnostics. Despite the maturity of the technique, two bottlenecks are identified which are addressed in this thesis: the achievable measurement volume size, and the optical access to geometrically complex objects. Both aspects are well illustrated...

Ring of fire as a novel approach to study cycling aerodynamics

The research presented in this thesis introduces a new measurement concept for on-site aerodynamic measurements based on large-scale stereoscopic particle image velocimetry (stereo-PIV) measurements past an athlete, a vehicle or an object travelling through a quiescent environment. The analysis of the momentumdeficit past the transit poses the...

Soap bubbles for large-scale PIV: Generation, control and tracing accuracy

Particle Image Velocimetry (PIV) relies upon the introduction of particle tracers that scatter sufficient light and follow the flow accurately. The use of submillimetre helium-filled soap bubbles (HFSB) as flow tracers for PIV is investigated for the purpose of enabling velocity measurements in large-scale industrial wind tunnels. That soap...

Cyclist Aerodynamic Drag Analysis through Large-Scale PIV

The use of large-scale particle image velocimetry (PIV) is proposed for cycling aerodynamic study to advance the general understanding of the flow around the rider and the bike, leading to new strategies for cycling aerodynamic drag reduction in the future. The investigation concentrates on the measurement of the wake velocity and its relation...

Development and application of helium-filled soap bubbles: For large-scale PIV experiments in aerodynamics

A new type of tracer is making its entry in the scenario of wind-tunnel measurements: helium-filled soap bubbles (HFSB). The present work discusses the main fluid-dynamic and optical properties of HFSB to evaluate their use for quantitative measurements in aerodynamic experiments.<br/>In the past three decades, particle image velocimetry (PIV)...

PIV Uncertainty Quantification and Beyond

The fundamental properties of computed flow fields using particle imaging velocimetry (PIV) have been investigated, viewing PIV processing as a black box without going in detail into algorithmic details. PIV processing can be analyzed using a linear filter model, i.e. assuming that the computed displacement field is the result of some spatial...