Flow Angularity Investigations in an Automotive Slotted Wall Wind Tunnel
1
Department of Mechanics and Maritime Science, Chalmers University of Technology, 412 96 Gothenburg, Sweden
2
Volvo Cars, PVT3, 405 31 Gothenburg, Sweden
*
Author to whom correspondence should be addressed.
Energies 2019, 12(23), 4575; https://doi.org/10.3390/en12234575
Received: 23 October 2019 / Revised: 19 November 2019 / Accepted: 22 November 2019 / Published: 30 November 2019
(This article belongs to the Special Issue Recent Advances in Vehicle Aerodynamics)
The Volvo Cars aerodynamic wind tunnel has had a vortical flow angularity pattern in the test section since its original commissioning in 1986. The vortical flow nature persisted after an upgrade in 2006, when the fan was replaced and a moving ground system was introduced. It has been hypothesized that the cause for this flow angularity pattern was leakages around the heat exchanger installed in the settling chamber. The present paper tests this hypothesis by measuring the flow angularity in the test section before and after sealing the leakages. The findings show that the leakage path around the heat exchanger does not influence the flow angularity, and that the current pattern is different compared to the commissioning after the upgrade. This prompted an investigation of the influence from the turbulence screens, which were changed after the upgrade commissioning. These investigations indicate that the probable cause of the vortical flow angularity pattern is residual swirl from the fan. Force measurements on a reference car with and without extra induced flow angularity show that the flow angles measured in the tunnel for regular operation are most likely small enough to not have a significant effect on the measured aerodynamic forces.
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Keywords:
wind tunnel; flow angularity; flow uniformity; slotted wall
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MDPI and ACS Style
Ljungskog, E.; Sebben, S.; Broniewicz, A. Flow Angularity Investigations in an Automotive Slotted Wall Wind Tunnel. Energies 2019, 12, 4575.
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