Wake Dynamics and Rotor - Fuselage Aerodynamic Interactions

摘要

The unsteady loads experienced by a helicopter are known to be strongly influenced by aerodynamic interactions between the rotor and fuselage; these unsteady loads can lead to deficiencies in handling qualities and unacceptable vibratory characteristics of the rotorcraft. This work uses a vorticity based computational model to study the governing processes that underpin this aerodynamic interaction and aims to provide greater understanding of the wake dynamics in the presence of a fuselage, as well as an appreciation of how the geometry of the wake affects the loading on the fuselage. The well-known experiments using NASA's ROBIN fuselage are used to assess the accuracy of the computations. Comparisons of calculations against results from smoke visualisation experiments are used to demonstrate the ability of the model to capture accurately the overall rotor wake geometry, and comparisons with inflow data from the experiments substantiates the ability of the method to capture the near-rotor aerodynamic environment. The fuselage model is able to predict accurately the unsteady fuselage loading that is induced by blade-passage and also by the inviscid interaction between the main rotor wake and fuselage.