Transonic Steady And Unsteady Aerodynamics For Wings Using Three Dimensional Euler Equations

Abstract

In this study, transonic aerodynamic analysis is performed for both rigid and flexible wings using the three-dimensional Euler equations. Computer codes for numerical analysis have been developed in the way of increasing their efficiency and generality for the steady and unsteady aerodynamic calculations. Time dependent, compressible Euler equations are solved numerically using a centraldifferenced finite-volume scheme and an Diagonalized Alternating Direction Implicit (DADI) algorithm. The DADI algorithm involves implicit second-order dissipation terms, and solves only scalar tridiagonal equations economically. When unsteady motions for wings are calculated, grid generation is performed by a blend of the rigid rotation and a linear interpolation method. Interconnection between structural nodal and aerodynamic grid points on a wing surface is performed using the surface spline method based on the infinite plate theory. The accuracy and efficiency of the present 3-D Euler programs are numerically demonstrated through the comparisons with experimental data for the ONERA M6 and the NACA64A010 wings. Generalized aerodynamic orces (GAFs) are analyzed and also compared with the other numerical results for the AGARD standard wing configuration. Finally, the effects of three major factors for the transient pulse method which affect the GAF results are investigated.