Degree Name

BS in Aerospace Engineering


Aerospace Engineering Department


Jin Tso


This paper investigates the flow characteristics of the renovated Cal Poly 3 x 4 ft subsonic wind tunnel. The IFA 300 constant-temperature anemometer along with a cross-plane X-wire dual-sensor probe was used to measure the mean velocity and turbulence intensity of the tunnel flow and part of the turbulent boundary layer at one section of the tunnel. Because of the malfunction of one channel of the IFA 300, only one wire of the dual sensor probe was calibrated for the measurements. The probe was then placed in a streamlined probe holder mounting on the traverse inside the wind tunnel. The turbulent boundary layer thickness was found to be 6 inches. Flow uniformity in the surveyed tunnel section was found to be acceptable with a maximum velocity deviation of 2.5%, and turbulence intensity throughout the vast majority of the tunnel section was found to be less than 0.5%. However, a region of high turbulence intensity (≈2.5%) was found at the top center of the tunnel, which requires further examination.