A harmonic balance method for nonlinear fluid structure interaction problems

Over the past decade the Harmonic-Balance technique has been established as a viable alternative to 26 direct time integration methods to predict periodic aeroelastic instabilities. This article reports the pro- 27 gress made in using a frequency updating procedure, based on a coupled fluid-structural solver using the 28 Harmonic-Balance formulation. In particular, this paper presents an efficient implicit time-integrator that 29 accelerates the convergence of the structural equations of motion to the final solution. To demonstrate 30 the proposed approached, the paper includes a detailed investigation of the impact of input parameters 31 and exercises the method for two types of fluid-structural nonlinear instabilities: transonic limit-cycle 32 oscillations and vortex-induced vibrations