Study on the Transonic Flows around a Thin Wing with an Aileron

Abstract

The experimental airplanes of Supersonic Transportation, SST, are being developed in Japan. The wings are thin to augment cruise aerodynamic performance. If these wings are equipped with ailerons, the shock wave motions on the ailerons might cause aileron buzz not accompanied by heavy separation of the boundary layers. On the other hand, unsteady aerodynamics research regarding thin wings has not been extensive. In order to precisely investigate the shock wave motions on thin wings, two-dimensional CFD simulations were conducted in our study. In the simulations, Navier-Stokes equations are solved around the NACA0003 airfoil with an oscillating aileron. The results show that the imaginary component of the unsteady aileron hinge moment, abbreviated "AHMI," has the maximum and positive value when the shock wave oscillates around the mid-chord on the aileron. The aileron length does not strongly affect the shock wave motions on the aileron if the scale of the shock wave motions is normalized with the aileron length. But a longer aileron shows larger AHMI than a shorter one. The experimental results on SST arrow wing are compared with simulated results, too. In order to compare the results acquired from the models having different space dimensions, the local Mach number component normal to the aileron hinge line is calculated as a common parameter. The comparison shows that, for both results, AHMI becomes positive when the shock wave oscillates around the aileron mid-chord. In addition, as the shock wave oscillates more rearward on the aileron, AHMI increases.