Applicability Research and Improvement of Modal Method in CFD/CSD Coupling Static Aeroelastic Analysis

As same as the inertia relief method, the modal method is also widely used in the static aeroelastic analysis of the free-free system. Few studies have been conducted to analyze the impact of these two methods on the static aeroelastic results. However, in fact, when the modal method is used for the static aeroelastic analysis, the coupling between rigid-body modes and elastic modes will exist, which resulting in the rigid-body deformation included in the elastic deformation. Especially for the rigid-body pitching deformation, which will change the actual angle of attack, and thus affect the aerodynamic derivatives. In this paper, two simulation models are used to study the difference between the modal method and the inertia relief method, and the deep-seated reason of this difference is also studied, to confirm the applicability of the modal method. In addition, a rigid-body deformation corrected method is proposed for the modal method, to eliminate the effect of rigid-body deformation in the modal method, and the corrected result matches with that received by the inertia relief method quite well.