Aerodynamic characteristics of passenger and transport aircraft models at harmonic oscillations on the pitch angle for high angles of attack

摘要

A systematic analysis has been performed for many-years experimental data obtained in the wind tunnel T-203 (SibNIA) for testing the models of passenger and transport aircraft for the case of harmonic oscillation at the pitch angle for low subsonic velocities. The key features of behavior of aerodynamic derivatives coefficients and dependencies of current values of normal force coefficient and longitudinal moment coefficient on the angle of attack have been demonstrated for the stalling modes of streamlining. It was demonstrated that at near-critical angles of attack, we have a strong dependency of aerodynamic derivatives of pitch moment on the normalized oscillation frequency for the range of natural values; this makes the traditional mathematical model of aerodynamic loads (uses the aerodynamic derivatives at fixed frequencies of oscillation) unfit for the considered scope of experimental tasks.