Aerodynamic commissioning results for the Korea Air Force Academy Subsonic Wind Tunnel

Meredith, Scott L.; Martindale, W. R.; Benetti-Longhini, L.; Boylan, D. E.; Chaney, M P

doi:10.2514/6.2000-290

Cited by 3 publications

(1 citation statement)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There are numerous examples in the literature of test section flow angularity measurements for subsonic and transonic wind tunnels [2][3][4][5][6][7][8][9][10][11][12][13][14][15], typically performed as part of commissioning activities during the start-up phase after construction or after an upgrade. However, investigations of the causes of flow angularity in the test section are less common.…”

Section: Introductionmentioning

confidence: 99%

Flow Angularity Investigations in an Automotive Slotted Wall Wind Tunnel

2019

View full text Add to dashboard Cite

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.

show abstract

Section: Introductionmentioning

confidence: 99%

Flow Angularity Investigations in an Automotive Slotted Wall Wind Tunnel

2019

View full text Add to dashboard Cite

show abstract

The low acoustic noise and turbulence wind tunnel of the University of Sao Paulo

et al. 2021

View full text Add to dashboard Cite

This paper introduces the Low Acoustic Noise and Turbulence (LANT) wind tunnel of the Sao Carlos School of Engineering, University of Sao Paulo (USP-EESC), Brazil. The closed-loop wind tunnel features several devices to improve flow uniformity, reduce swirl, and lower the background acoustic noise and turbulence, enabling stability and aeroacoustic experiments. The design criteria was based on the best practices reported, in particular for low turbulence wind tunnels. Yet, these criteria are conflicting and we discuss the decisions that had to be made and present flow quality results that were achieved. The 16-bladed axial fan with 13-blade stators is driven by a variable-speed electric motor. At the corners, 100 mm dense acoustic foam is installed on the vertical walls, floor and ceiling, and the turning vanes are filled with acoustic-absorbing material. The long settling chamber contains a 3.175 mm mesh hexagonal honeycomb and five fine mesh nylon screens, ending in a 7:1 area ratio short contraction. The 3-m long closed-working section has a $1\times 1\ {\rm m}^2$ cross-section area. At 15 m/s the working section wall boundary layer is less than 100 mm thick, providing an area of at least $800\times 800\ \mathrm{mm}^2$ where the streamwise flow uniformity was within 1%. In the 10–30 m/s flow speed range, the turbulence intensity ranged from 0.05% to 0.071% and the background acoustic noise level, obtained with an inflow microphone, ranged from 90 and 110 dB. A benchmark experiment on a flat plate boundary layer produced an almost perfect two-dimensional Blasius profile up to $Re_x \approx 2.5 \times 10^6$ . A beamforming benchmark experiment on aeroacoustics accurately identified the sound emitted by a cylinder immersed in the flow.

show abstract