Thin-Wing Vibration Control Using Flexible Fins

Abstract

This paper describes thin-wing vibration control using an array of small flexible rectangular polymer fins attached near the leading edge on the upper wing surface to manipulate unsteady flow structures. Dynamic aeroelastic deformation of a rectangular flat-plate wing and motions of the fins relative to the wing are measured by using a high-speed videogrammetric system in a low-speed wind tunnel. The major vibration modes of the baseline wing and the wing with the fins are extracted. It is found that wing vibration particularly near the dominant first torsion mode is considerably suppressed by the flexible fins interacting with highly unsteady separated flows in the ranges of the freestream velocities and angles of attack. Global velocity measurements indicate that the fins significantly reduce the unsteadiness of the separated flow on the wing. The physical mechanisms behind the vibration suppression with the flexible fins are explored based on the analysis of the measured data.