HFSB-seeding for large-scale tomographic PIV in wind tunnels

HFSB-seeding for large-scale tomographic PIV in wind tunnels

Caridi, Giuseppe Carlo Alp (TU Delft Aerodynamics)
Ragni, D. (TU Delft Wind Energy)
Sciacchitano, A. (TU Delft Aerodynamics)
Scarano, F. (TU Delft Flow Physics and Technology)

Flow Physics and Technology

2016-12-01

A new system for large-scale tomographic particle image velocimetry in low-speed wind tunnels is presented. The system relies upon the use of sub-millimetre helium-filled soap bubbles as flow tracers, which scatter light with intensity several orders of magnitude higher than micron-sized droplets. With respect to a single bubble generator, the system increases the rate of bubbles emission by means of transient accumulation and rapid release. The governing parameters of the system are identified and discussed, namely the bubbles production rate, the accumulation and release times, the size of the bubble injector and its location with respect to the wind tunnel contraction. The relations between the above parameters, the resulting spatial concentration of tracers and measurement of dynamic spatial range are obtained and discussed. Large-scale experiments are carried out in a large low-speed wind tunnel with 2.85 × 2.85 m² test section, where a vertical axis wind turbine of 1 m diameter is operated. Time-resolved tomographic PIV measurements are taken over a measurement volume of 40 × 20 × 15 cm³, allowing the quantitative analysis of the tip-vortex structure and dynamical evolution.

http://resolver.tudelft.nl/uuid:f961c1cd-10f0-44c0-8504-853ae810ea68

https://doi.org/10.1007/s00348-016-2277-7

0723-4864

Experiments in Fluids: experimental methods and their applications to fluid flow, 57 (12)

Institutional Repository

journal article

© 2016 Giuseppe Carlo Alp Caridi, D. Ragni, A. Sciacchitano, F. Scarano