Design of a traverse system for the characterization of a large-scale wind tunnel

2022-9
Ulu, Tunahan
This study presents the design and simulations of a traverse system and preliminary characterization measurements of the RÜZGEM large-scale wind tunnel. In the first phase of the study, the traverse system was simulated aerodynamically using computational fluid dynamics (CFD) tools. The effects of the rectangular, whole profile and partial profile traverse mechanisms on the measurements were examined. The probe lengths were studied in detail to determine the most suitable length. According to the simulations, the expected maximum error is 1.3% for velocity measurement. In the second phase of the study, the simulated traverse system is integrated to wind tunnel test sections. The dynamic stability was measured as ±9% in the boundary layer test section (BLTS) at a freestream of 14.8 m/s, which is at the same level as the uncertainty range of the pressure scanner. The dynamic stability in the aeronautical test section (ATS) was obtained as ±1% and ±0.5% at freestream velocities of 35.1 m/s and 70.9 m/s, respectively. The velocity distribution in the measured plane of BLTS and ATS shows that 60% and 5% variation from the center to the wall are expected for test sections, respectively. In terms of angularity in test sections of RÜZGEM, 4° pitch angle in BLTS and 3° pitch angle in ATS were measured. In order to assess the effect of the traverse system on the angularity measurements, 2D simulations and measurements with a strut-type support system were performed. The results of the simulations revealed that the lateral support of the traverse system causes 3° of flow deviation in the five-hole probe position. This is also justified by the decreasing measured pitch angle obtained in the measurements with a strut-type support system. These results suggest that the traverse system influences flow angularity measurements in the wind tunnel and should be re-configured for proper characterization measurements.

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Citation Formats
T. Ulu, “Design of a traverse system for the characterization of a large-scale wind tunnel,” M.S. - Master of Science, Middle East Technical University, 2022.