Transverse gust generation in a wind tunnel: a suction-driven approach

The Andrew Fejer Unsteady Wind Tunnel was modified to add a suction duct on top of the test section to generate a vertical velocity component (cross flow). The suction produced on the top was distributed by the individually controlled louvers at the inlet of the suction duct so that the velocity components in the test section vary both temporally and spatially. Steady and traveling-wave transverse flows were generated in the test section. We present theoretical models for the unsteady flow field generated by this configuration and validate these models with experimental measurements. The results indicated that the transverse gusts generated in the test section were essentially irrotational, and a potential flow model makes relatively accurate predictions of the flow field. The suction-driven approach greatly reduced the turbulence level in the flow field relative to jet-driven cross flow approaches, and demonstrated high levels of repeatability. Traveling waves in 1-cos form were generated and showed evident influence on the flow angle of attack. Graphical abstract