Efficient Method for Computations of Three-Dimensional Unsteady Transonic Aerodynamics.

摘要

For aeroelastic application, the present Transonic Equipment Strip (TES) method has established an efficient and cost effective procedure for unsteady flow computations of arbitrary wing planforms including control surface. According to the nature of three dimensional unsteady transonic flow, a method based on the TES model is developed which consists of two consecutive correction steps to a given unsteady two-dimensional code. The latter could be a time-linearized transonic code or a nonlinear one such as the LTRAN2 code. The correction steps are: first, the mean-flow correction step which involves an equivalent airfoil design procedure; and second, the spanwise phase correction step which accounts for the effects of acoustic wave propagation in three dimensions. Computed results using the TES method are compared with those obtained by current methods such as results using the TES method are compared with those obtained by current methods such as various versions of the XTRAN3S code, Isogai's full potential code, and measured data provided by the National Aerospace Laboratory and the Royal Aeronautical Establishment. Computed cases included rectangular wings in pitching and bending oscillations, the Northrop F-5 wing in pitching oscillation, the AGARD standard RAE wing with an oscillating flap, and the LANN wing in pitching oscillation. Assessments of the present approach and other existing methods are given. (KR)