Modification and calibration of the Naval Postgraduate School Academic Wind Tunnel

Abstract

Since the early 1980's, the Academic Wind Tunnel has operated with only one half its designed power section. Resultant flow qualities have limited the use of this facility. A damping screen was installed in the settling chamber to reduce the level of turbulence intensity in the tunnel. Following this modification, calibration measurements in the vertical centerplane were performed to document flow conditions in the test section. The tunnel calibration investigated lateral pressure variations, flow angularity, and turbulence intensity and included an airspeed calibration. When available results were compared to data from calibrations performed before the tunnel modification. Result indicate the total and static pressure lateral variation is within 1.0% angular variation of approximately +/- 1.0% exists in the test section, and a 25.0% reduction in turbulence intensity was obtained due to the presence of the damping screen. Flow separation in the diffuser is believed to be influencing total pressure oscillation in the test section.