EFFECTS OF ANGLE OF ATTACK AND AIRFOIL PROFILEnON THE TWO-DIMENSIONAL FLUTTER DERIVATIVES FOR AIRFOILS OSCILLATING IN PITCH AT HIGH SUBSONIC SPEEDS

摘要

Two-dimensional aerodynamic lift and moment flutter derivatives are presented for moderate and high angles of attack for several airfoil profiles varying in thickness and thickness distribution. The derivatives were evaluated from data obtained by means of pressure cells for models oscillating about the quarter-chord axis at mean angles of attack of 4° and 8° (and for one model at 10°) for amplitudes of ±1°, for frequencies up to 40 cycles per second, and for a range of Mach numbers including values which lead to either partially stalled or supercritical flow. Reduced frequency varied from about 0.12 to 1.2 at M = 0.2, and from 0.03 to 0.30 at M = 0.86. Reynolds number based on the airfoil "chord varied from 3 million to 8 million.