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CFD simulation of flapped rotors

Published online by Cambridge University Press:  27 January 2016

F. Dehaeze ,
K. D. Baverstock  and
G. N. Barakos
F. Dehaeze*
Affiliation:
CFD Laboratory, School of Engineering, University of Liverpool, Liverpool, UK
K. D. Baverstock*
Affiliation:
AgustaWestland, Yeovil, UK
G. N. Barakos*
Affiliation:
CFD Laboratory, School of Engineering, University of Liverpool, Liverpool, UK
*
florent.dehaeze@agustawestland.com
karl.baverstock@agustawestland.com
george.barakos@glasgow.ac.uk
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Abstract

The use of active trailing edge flaps on rotors may lead to performance benefits as well as noise and vibration reduction. In this work, computational fluid dynamics, using the HMB2 solver, is used to assess the effect of the trailing edge flaps on the whole flight domain of a modern main rotor. Starting from a baseline blade design, multiple techniques are demonstrated. The flap is first assessed using 2D pitching aerofoil simulations, followed by dMdt simulations, that account for the simultaneous variations of pitch and Mach around the azimuth. It was shown that enhanced lift was obtained while inspection of the moment coefficient showed negative damping for the flap for a limited set of conditions. Due to the 2D formulation, dMdt computations are fast to perform and can be used to inform codes predicting the rotor performance. The flap was then assessed in hover, and only allowed for limited improvement in blade performance at high thrust. In forward flight, the flap was actuated at a frequency of 1 per revolution, and was found to have a strong effect on the loads on the retreating side. The effect on the moments was even stronger. The flight envelope of the blade was explored, and clean and flapped cases were compared. The most noticeable changes occur at high and medium thrust. The CFD method was found to be efficient and robust, without any substantial penalties in CPU time, due to the flap modelling, over the tested conditions.

Type
Research Article
Information
The Aeronautical Journal , Volume 119 , Issue 1222: A Rotorcraft Special Issue , December 2015 , pp. 1561 - 1583
Copyright
Copyright © Royal Aeronautical Society 2015

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