Wind Tunnel Investigation of Pressure Distribution and Transition Position of a Swept 3D Wing

Extensive wind tunnel tests are conducted to evaluate surface pressure distribution of a semi span swept wing. The wing section has a laminar flow airfoil similar to NACA 6-series airfoils. The investigations are conducted at various speeds and angles of attack. Surface pressure distribution over the wing upper surface is measured for both chordwise and spanwise sections. Statistical analyses are performed on the data to realize the transition point at each chordwise section. The 3D pressure profiles are compared to the corresponding 2D results at the same conditions. Calculation of the standard deviation, SD, of time variable pressure data shows that SD increases in the transition area and then decreases again when the flow becomes fully turbulent downstream. The measured transition points are further compared with 2D computational results.