Reduced Order Transonic Aeroelastic Gust Response Simulation of Large Aircraft

Abstract

Reduced order modelling of large civil aircraft under gust excitation in transonic flight is discussed to enable computational fluid dynamics for routine gust load analysis. The impact of the elastically deforming structure is captured by tracing eigenmodes which originate in the structure, using the Schur complement method. Such global aeroelastic modes are computed for a case with nearly 48 million degrees of freedom. The gust response behaviour of the same full order system is sampled by computing complex-valued sinusoidal gust responses at several discrete frequencies. Modes representing the gust influence are obtained from the proper orthogonal decomposition technique which solves a small eigenvalue problem correlated to the sampling data. Afterwards, both sets of modes are combined and the linearised operator of the Reynolds-averaged Navier-Stokes equations is projected onto the coupled subspace. The obtained reduced order model can be solved in a rapid fashion to investigate various gust parameters