CFD-Based Aerodynamic Shape Optimization of Hovering Rotors

Allen, Christian B; Morris, Asa; Rendall, Thomas

doi:10.2514/6.2009-3522

Cited by 9 publications

(2 citation statements)

References 40 publications

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“…The University of Bristol created a similar optimization loop using a nonlinear programming algorithm as optimizer and CFD simulations for the flow analysis. 5 Radial Basis Functions were used to manage mesh deformations induced by geometrical changes. Even if the obtained mesh was of high quality, a large number of parameters was to be specified to perform a simple twist optimization.…”

Section: Introductionmentioning

confidence: 99%

Aerodynamic rotor blade optimization at Eurocopter - a new way of industrial rotor blade design

Leusink¹,

Alfano²,

Cinnella

et al. 2013

51st AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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Industrial aerodynamic design optimization of helicopter rotor blades requires employment of multi-objective optimization methods to account for the two distinct objectives in hover and forward flight. Genetic algorithms are preferred for finding the Pareto Optimal Front, as they allow the engineer to select out of optimal designs. An optimization loop is created, coupling the Dakota optimization library and two simulation methods for objective function evaluation: comprehensive rotor code HOST and CFD solver elsA. For low-cost rotor simulations by HOST, a genetic algorithm is employed to maximize hover and forward flight rotor performance in single-and two-point optimizations. Twist and chord laws of the 7A blade are optimized separately and simultaneously. As genetic algorithms require too many cost function evaluations for CFD-based optimizations, Surrogate Based Optimization (SBO) is employed. SBO is initialized by a preliminary Design of Experiment (DoE). The results are used to generate a metamodel for estimation of cost function evaluations in the optimization algorithm. The metamodel is updated using information from subsequent simulations. Validation of HOST-based SBO against full genetic algorithm optimizations shows that the Pareto Optimal Front is correctly represented by SBO, while requiring 88% less cost function simulations. Several sizes of initial DoE, number of update cycles and number of simulations added per cycle are tested. Then, a similar SBO optimization is carried out by replacing the HOST code by CFD for hover performance simulation. The results demonstrate the ability of both solvers and both optimization techniques to perform aerodynamic design optimization of helicopter rotor blades. NomenclatureHOST Helicopter Overall Simulation Tool GA Genetic Algorithm RSM Response Surface Method SBO Surrogate Based Optimization F.M.Figure of Merit (measure for rotor performance in hover) L/D Lift-over-Drag ratio (measure for rotor performance in forward flight)

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Section: Introductionmentioning

confidence: 99%

Aerodynamic rotor blade optimization at Eurocopter - a new way of industrial rotor blade design

Leusink¹,

Alfano²,

Cinnella

et al. 2013

51st AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

View full text Add to dashboard Cite

show abstract

“…Walsh et al [31] automatically determined chord and The University of Bristol developed a similar optimization loop for rotor blades in hover, using an optimizer based on a nonlinear programming algorithm and CFD simulations for the flow analysis [3,4]. Radial basis functions were used to manage mesh deformations induced by geometrical changes: this allowed ensuring high computational mesh quality; nevertheless, a large number of parameters was to be specified, even to perform a simple twist optimization [5].…”

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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Parametric structure optimization of a main rotor blade as an application for FSI analysis in main rotor optimization process

Kocjan,

Rogólski

2024

AEAT

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Purpose Modern warfare and modern battlefield are very demanding. The recent conflicts showed that the usage of the helicopters is very limited and only the best constructions are able to provide support for the operations. The purpose of this research is to show the possibilities of new design tool for main rotor aerostructural optimization. It is a next chapter of the research that is aimed at finding new solutions for rotorcraft constructions. Design/methodology/approach This work presents a method of preliminary structure optimization of the main rotor blade using parametric modeling. It is the next step in the main rotor optimization studies. It is the next step after preparing the parametric model for the external shape CFD analysis. As a basis for parametric blade structure calculations, the analytical model is provided in this paper. The equations of rigid blade loads and, as a consequence of the strength elements, stresses are shown. The parametric blade modeling is conducted using the Graphic Integrated Programming language. The parametric design method is shown to be used for various blade planform models and different section airfoils. The structure of a blade is generated automatically after the user enters the parameters. The code-inbuilt analysis systems provide a quick inertia examination of the generated geometry, which is the basis for further optimization. The program calculates the blade loads and verifies them with the given material conditions and proposed safety factors. In the analysis, composite materials for the strength elements were proposed. Findings The results of this research showed the application of parametrization into the main rotor blade design loop. It was presented that the main rotor blade structure can be enhanced using fluid-structure interaction (FSI) methods. The time saving with the implementation the process into design loop is shown. Practical implications This work can be practically used in the main rotor blade design process. It provides the possibilities to check various blade aerodynamic configuration in a structure strength aspect. Originality/value To the best of the authors’ knowledge, there were no published research that combines the main rotor FSI analysis. The method, which is presented in the work, provides a new approach to a rotorcraft design. The application of the parametrization and combining it with the FSI method gives a novel solution for helicopters construction enhancement.

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CFD-Based Aerodynamic Shape Optimization of Hovering Rotors

Cited by 9 publications

References 40 publications

Aerodynamic rotor blade optimization at Eurocopter - a new way of industrial rotor blade design

Aerodynamic rotor blade optimization at Eurocopter - a new way of industrial rotor blade design

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

Parametric structure optimization of a main rotor blade as an application for FSI analysis in main rotor optimization process

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