Some Measurements of Wing Buffeting on a Flutter Model of a Typical Strike Aircraft.

摘要

Some measurements of buffeting were made on a 1/30 scale complete flutter model of the wing of a typical strike aircraft. The tests covered the Mach number range from M = 0.45 to 0.94 and the Reynolds number range from R = 0.6 x 10 to the 6th power to 1.7 x 10 to the 6th power. With a clean wing, buffeting measurements were made over a wide range of Reynolds number at constant Mach number to derive the buffet excitation parameter at the wing fundamental bending frequency of 170 Hz. The complete flutter model had a rigid body freedom of rotation in roll at a frequency of about 39 Hz, and indicated the onset of 'wing rock', well above the buffet onset boundary. The wing rock started close to the maximum limit of buffet penetration achieved in flight. Significant variations in aerodynamic damping were measured with flow separations for both the low frequency roll mode and the higher frequency first wing bending mode. For the roll mode these variatons may be predicted by quasi-steady strip theory, but not for the fundamental bending mode. This difference indicates an important frequency effect on the separated flows, particularly at subsonic speeds. These tests indicate some limitations of buffeting measurements on ordinary wind tunnel models, particularly for half models. (Author)