An Aeroelastic Harmonic Balance Solver Using High-Order CFD W.Yao * , S.Marques † School of Mechanical and Aerospace Engineering Queen’s University, Belfast, UK, BT9 5AH Abstract: The effort integrates high order MP scheme into HB framework for Limit Cycle Oscillations (LCOs) prediction, with the goal of computational cost reduction. The work heavily relies on a novel approach for LCOs computation presented in previous work [1]. The HB solver with high order MP scheme implementation or high order HB solver is first demonstrated by forced motion, AGARD CT5 case, and proven to have significant accuracy improvement in terms of lift/moment coefficients as well as flow field. A two-dimensional aero-elastic system further proves that high order HB solver is capable of predicting LCOs amplitude and frequency accurately with coarse grid, and at least two times faster than 2 nd order HB solver. Nomenclature b,c = semi chord and chord, respectively M ∞ = freeestream Mach number x m = Moment center α,h = pitch and plung displacement α m ,α 0 = mean angle of attack and pitch oscillation amplitude m = wing mass S α = first moment of inertia of airfoil about elastic axis I α = second moment of inertia of airfoil about elastic axis x α = airfoil static unbalance x α= S α /(mb) r α = Radius of gyration of airfoil about elastic axis, r α =√I α /(mb) C L ,C M = lift and moment coefficient, respectively ω h , ω α = pitch and plung natural frequency U ∞ = freestream velocity V = reduced freestream speed µ = mass ratio ω,κ = frequency and reduced frequency, respectively, κ=ω/ (U ∞ b) τ = Pseudo time step A = Harmonic Balance frequency domain matrix D = Harmonic Balance operator matrix * Research Fellow † Lecture