Soap bubbles for large-scale PIV in industrial wind tunnels
D. E. Engler Faleiros (Royal Netherlands Aerospace Centre NLR, TU Delft - Aerodynamics)
Marthijn Tuinstra (Royal Netherlands Aerospace Centre NLR)
Bart van Rooijen (German-Dutch Wind Tunnels (DNW))
F. Scarano (TU Delft - Flow Physics and Technology)
Andrea Sciacchitano (TU Delft - Aerodynamics)
More Info
expand_more
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.
Abstract
This work evaluates the use of helium-filled soap bubbles (HFSB) for Particle Image Velocimetry (PIV) measurements at high Reynolds numbers (up to 3.2 million) in aeronautics. The measurements are performed in the Low Speed Tunnel (LST) of the German-Dutch Wind Tunnels (DNW) using a high-lift airfoil in close-to-stall conditions up to 70 m/s. Experiments using Di-ethylhexyl- sebacat (DEHS) particles are performed for a comparison of the two seeding techniques. The signal to noise ratio of HFSB images was two orders of magnitude larger than that of DEHS, which strongly reduced the unwanted effects of background reflections and light intensity spatial variations, compared to DEHS particle images. The mean velocity field obtained with HFSB exhibits differences typically within 1% of the free stream velocity, when compared to DEHS measurements.