The Experimental Generation of Streamwise Gusts and their Impact on a Finite-Span Wing

Under normal operation, aircraft and wind turbines frequently encounter gusts, or discrete unsteady variations in the direction and magnitude of the freestream velocity. Streamwise gusts, which impose changes in the magnitude of the freestream, can dramatically alter the aerodynamic response of these systems when the gust length-scales, time-scales or magnitudes are commensurate with the steady operating conditions of these systems. To study these interactions a unique unsteady low-speed wind tunnel facility was constructed at the University of Colorado Boulder which can generate both convective and global streamwise velocity disturbances. The design, modeling, and performance of this facility will be presented along with the aerodynamic response of a canonical finite-span rectangular wing section to a time-varying freestream. More specifically, the seminar will focus on how the convective nature of the streamwise velocity disturbances can couple with wing sweep to impose dramatic variations in the pitching moment response of a simple wing section. In addition to this primary topic, a summary of other basic research efforts ongoing in the Experimental Aerodynamics Laboratory at the University of Colorado Boulder will also be given.