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Abstract. This research aims to investigate a virtual blade model and assess rotor influence on helicopter fuselage aerodynamics. The rotor disk is discretized in the azimuthal direction, and a time-varied pressure jump is applied in regions occupied by the blades. To obtain the pressure jump, an actuator disk is employed using uniform and non-uniform blade load distribution, based on momentum theory.

CFD predictions of rotor loads and vibration could be improved by resolving a larger part of the turbulent flow spectrum around the rotor. CFD methods, currently in use for rotors blades, employ the URANS approach that is inherently limited in terms of the sizes and frequencies of the resolved local flow structures. This paper attempts to apply hybrid (DES) method of turbulence modelling and simulation aiming to resolve a larger part of the spectrum around rotor blades in hover and forward flight. A comparison between DES and URANS was carried out for the case of a forward flying rotor suggesting that DES has potential for rotor applications. The limitations of the available experiments for CFD validation are also highlighted.

Abstract:In this work, fully-resolved rotor-fuselage interactional aerodynamics is used as the forcing term in a model based on the Euler-Bernoulli equation, aiming to simulate helicopter tail-boom vibration. The model is based on linear beam analysis and captures the effect of the blade-passing as well as the effect of the changing force direction on the boom. The Computational Fluid Dynamics (CFD) results were obtained using a well-validated helicopter simulation tool. Results for the tail-boom vibration are not validated due to lack of experimental data, but were obtained using an established analytical approach and serve to demonstrate the strong effect of aerodynamics on tail-boom aeroelastic behavior.

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