Aeroelastic Modeling of the AGARD 445.6 Wing Using the Harmonic-Balance-Based One-Shot Method

Abstract

The harmonic-balance-based one-shot method is developed for modeling the aeroelastic response of three-dimensional configurations such as aircraft wings in transonic flow regimes. This approach computes both of the fluid and structure fields by integrating respective harmonic-balance forms of governing equations in pseudotime, and variables of both fields are converged simultaneously in one shot. Several significant advantages of this code-coupling approach are observed. First, the computational cost is nearly independent of the number of structural modes retained in the analysis, which offers substantial computational efficiency over traditional aeroelastic solution techniques. Second, the solution of the two fields needs not be time synchronized, unlike what is required in traditional dual-time-stepping time-accurate approaches. This allows two solvers to use respective optimal physical time steps (different number of harmonics), different (optimal) pseudotime steps, as well as different integration techniques (explicit or implicit) to achieve the fastest convergence rates. The two operational modes of the one-shot method, which requires either the reduced velocity or the vibration amplitude as the main input, are discussed in detail. Numerical results of the AGARD 445.6 wing model show that the one-shot method can very rapidly predict the flutter boundary as well as the limit-cycle-oscillation response, offering a promising new technique to solve dynamic aeroelasticity problems.