Optimising Aspects of Rotor Blades in Forward Flight

Johnson, Catherine S.; Barakos, George N.

doi:10.2514/6.2011-1194

Cited by 17 publications

(13 citation statements)

References 14 publications

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“…The parameterisation method is also important as it must represent the design accurately with as few parameters as possible for the full process to work efficiently. The development of the method is documented in Johnson and Barakos (2010a, 2010b, 2011. To demonstrate the capabilities of this method, the optimisation of the rotor tip of the UH60-A rotor blade in forward flight is used.…”

Section: Research Objectivesmentioning

confidence: 99%

Optimisation of aspects of rotor blades in forward flight

Johnson

Woodgate

Barakos

2012

IJESMS

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This work presents a method for the optimisation of aspects of rotor blade shape in forward flight. The proposed technique employs CFD in conjunction with artificial neural networks (ANNs) and genetic algorithms (GAs). The developed method was used to optimise the anhedral and sweep of the UH60-A rotor blade in forward flight. A parameterisation method was defined, a specific objective function was created using the initial CFD data and the metamodel was used for evaluating the objective function during the optimisation. The obtained results suggest optima in agreement with engineering intuition but provide precise information about the shape of the final lifting surface and its performance. The results were checked using different optimisation methods and metamodels and were not sensitive to the employed techniques with substantial overlap between the outputs of the selected methods. The main CPU cost was associated with populating the CFD database necessary for the metamodel.

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Section: Research Objectivesmentioning

confidence: 99%

Optimisation of aspects of rotor blades in forward flight

Johnson

Woodgate

Barakos

2012

IJESMS

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“…There are also two distinct flow regimes, hover and forward flight, and good performance in one is unlikely to be carried over to the other. Aerodynamic optimisation has been applied previously to rotors in hover but mainly with both low fidelity aerodynamics and only gross geometric changes, see for example (13) , with only a few notable results using compressible CFD, namely those of ONERA (14,15) , Nadarajah et al (16) , Choi et al (17) , Nielsen et al (18) , Imiela (19,20) , and recent work of Johnson and Barakos (21,22) . The research presented here is aimed at the development of a modularised, generic optimisation tool, that is flow-solver and mesh type independent, and applicable to any aerodynamic problem; rotor blades in hover in this case.…”

Section: Interpolation Formulationmentioning

confidence: 99%

Aerodynamic shape optimisation of hovering rotors using compressible CFD

Allen

Rendall²

2011

Aeronaut. j.

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Generic wrap-around shape optimisation technology is presented, and is applied to a helicopter rotor in hover, using compressible CFD as the aerodynamic model. An efficient domain element shape parameterisation method is used as the surface control and deformation method, and is linked to a radial basis function global interpolation, to provide direct transfer of domain element movements into deformations of the design surface and the CFD volume mesh. This method is independent of mesh type and size, and optimisation independence from the flow solver is achieved by obtaining sensitivity information for an advanced parallel gradient-based algorithm by finite-difference. The method is applied here to a two-bladed hovering rotor, with transonic tip speed, comparing the effects of global twist parameters and more local planform parameters. Significant torque reductions are achieved in both cases, and it is shown that using only three global twist parameters are extremely effective. Using 63 local and global parameters, large geometric changes are demonstrated, with both induced power and wave drag reduced.

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“…For instance, Ref. [18] and [19] discuss a SBO based on the combination of a genetic algorithm with a Neural-Network reconstruction of the response surface from a limited number of CFD simulations for the optimization of dihedral and sweep distributions in forward flight.…”

Section: Introductionmentioning

confidence: 99%

Multi-fidelity optimization strategy for the industrial aerodynamic design of helicopter rotor blades

Leusink

Alfano

Cinnella

2015

Aerospace Science and Technology

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. AbstractThe industrial aerodynamic design of helicopter rotor blades needs to consider the two typical flight conditions of hover and forward flight simultaneously. Here, this multi-objective design problem is tackled by using a genetic algorithm, coupled to rotor performance simulation tools. The turn-around time of an optimization loop is acceptable in an industrial design loop when using low-cost, low-fidelity tools such as the comprehensive rotorcraft code HOST, but becomes excessively high when employing high-fidelity models like CFD methods. To incorporate high-fidelity models into the optimization loop while maintaining a moderate computational cost, a Multi-Fidelity Optimization (MFO) strategy is proposed: as a preliminary step, a HOST-based genetic algorithm optimization is used to reduce the parameter space and select a set of blade geometries used for initializing the high-fidelity stage. Secondly, the selected blades are re-evaluated by CFD and used to construct a high-fidelity surrogate model. Finally, a Surrogate Based Optimization (SBO) is carried out and the Pareto optimal individuals according to the SBO are recomputed by CFD for final performance evaluation. The proposed strategy is validated step by step. It is shown that an industrially acceptable number of CFD-simulations is sufficient to obtain blade designs with a significantly higher performance than the baseline and then SBO results issued from a standard Latin-Hypercube-Sampling initialization. The proposed MFO strategy represents an efficient method for the simultaneous optimization of rotor blade geometries in hover and forward flight.

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Optimising Aspects of Rotor Blades in Forward Flight

Cited by 17 publications

References 14 publications

Optimisation of aspects of rotor blades in forward flight

Optimisation of aspects of rotor blades in forward flight

Aerodynamic shape optimisation of hovering rotors using compressible CFD

Multi-fidelity optimization strategy for the industrial aerodynamic design of helicopter rotor blades

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