AN INTEGRATED AIRLOADS-INFLOW MODEL FOR USE IN ROTOR AEROELASTICITY AND CONTROL ANALYSIS

This paper offers an integrated airloads-inflow model that is ideally suited for rotor aeroelasticity and control analysis, especially for c ases in which eigenvalues are desired. The airloads model is derived f rom a rigorous application of thin-airfoil theory with an extension to allow for other airfoil effects, including ONERA type dynamic stall. The result is a hierarchical lift model that can be simplified down to any level including conventional 2-D strip theory. The inflow model i s a complete 3-D representation of shed and trailing vorticity with a skewed cylindrical wake. The inflow is expanded in shape functions whi ch can be truncated to any desired texture. Both models are written in closed-form state-variable equations with no hidden states and no int egrals over the wake. The coupling between these models (and with any structural model) is effected through simple geometric relationships. The result is a unified rotor analysis in terms of ordinary differenti al equations for lift, inflow, and structure.