The design and installation of a turbulence reduction system for the NASA Ames 11- by 11-foot Transonic Wind Tunnel

Murthy, Sreedhara V.; Kmak, Frank J.; Koss, Brian

doi:10.2514/6.1998-2705

Cited by 5 publications

(2 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Their findings are in line with Barlow et al [17], who provide some guidelines on how to minimize flow angularity, and state that regions of vortexlike flow in the test section often are the result of non-uniform flow upstream of the third corner, or of over-or underturned flow in the forth. In a work by Murthy et al [18], extensive measurements were gathered in the settling chamber and test section of a transonic tunnel in order to design a turbulence reduction system. A later work by Amaya and Murthy [19] reports that the constructed turbulence reduction system, consisting of a honeycomb and two screens, did reduce the flow angularity, especially the yaw component.…”

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

“…[1,2] The Wide-Angle Diffuser (WAD) is located in the 11-By 11-Foot Tunnel drive leg, downstream of the compressor and annular diffuser and directly upstream of the tunnel aftercooler. The WAD has a 60-degree included angle.…”

Section: Tunnel Flow Quality Improvementsmentioning

confidence: 99%

Modernization and activation of the NASA Ames 11- by 11-Foot Transonic Wind Tunnel

Kmak

2000

21st Aerodynamic Measurement Technology and Ground Testing Conference

Self Cite

View full text Add to dashboard Cite

The Unitary Plan Wind Tunnel (UPWT) was modernized to improve performance, capability, productivity, and reliability. Automation systems were installed in all three UPWT tunnel legs and the Auxiliaries facility. Major improvements were made to the four control rooms, model support systems, main drive motors, and main drive speed control.Pressure vessel repairs and refurbishment to the electrical distribution system were also completed. Significant changes were made to improve test section flow quality in the 11-By 11-Foot Transonic leg. After the completion of the construction phase of the project, acceptance and checkout testing was performed to demonstrate the capabilities of the modernized facility. A pneumatic test of the tunnel circuit was performed to verify the structural integrity of the pressure vessel before wind-on operations. Test section turbulence, flow angularity, and acoustic parameters were measured throughout the tunnel envelope to determine the effects of the tunnel flow quality improvements.The new control system processes were thoroughly checked during wind-off and wind-on operations.Manual subsystem modes and automated supervisory modes of tunnel operation were validated. The aerodynamic and structural performance of both the new composite compressor rotor blades and the old aluminum rotor blades was measured. The entire subsonic and supersonic envelope of the 11-By 11-Foot Transonic leg was defined up to the maximum total pressure.

show abstract