Computational investigations of active flow control on helicopter - rotor blades

Abstract

The paper presents results of the first stage of the research conducted within the frames of Active Rotor Technologies, which is the dynamically developed sub-domain of Rotorcraft Engineering. The research concerned a computational modelling and investigations of new solutions aiming at improvement of performance of modern helicopters and their environmental impact, by active control of operation of their rotors. The paper focuses on one of such solutions applied for the active control of airflow around helicopter-rotor blades. This solution is the Active Gurney Flap – a small, flat tab located at a pressure side of rotor blade near its trailing edge, which is cyclically deployed and stowed during rotation cycles of the blade. The Active Gurney Flap seems to be very promising solution which will enable helicopters to operate with reduced power consumption or reduced main rotor tip speed whilst preserving current flight performance capabilities, especially in terms of retreating blade stall. The newly developed methodology of computational modelling of active-flow-control devices, like Active Gurney Flap, applied for enhance a helicopter performance and improve its environmental impact, has been presented. Development of the methodology was the challenging task, taking into account strongly unsteady character of modelled phenomena and large differences of scales in both the space and time domain, where very small, dynamically deflected tab strongly influences the flow around rotating, large main rotor. Exemplary CFD simulations, presented in the paper, have been conducted to validate developed methodology.