Optimisation of aspects of rotor blades in forward flight

Johnson, Catherine S.; Woodgate, M.; Barakos, George N.

doi:10.1504/ijesms.2012.044846

Cited by 9 publications

(7 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Another important aspect is the need to balance a rotor design between hover and forward flight. This is one of the reasons why so many different rotor designs are seen across the globe, with examples shown in Figure 1 [2]. A BERP (British Experimental Rotor Programme) planform is used nearly solely in the UK, whereas other regions of the world tend to use simpler designs such as a swept/swept-tapered or a parabolic tips as discussed by Brocklehurst and Barakos [3].…”

Section: Introductionmentioning

confidence: 99%

Validation of the Steady-State Hover Formulation for Accurate Performance Predictions

et al. 2019

View full text Add to dashboard Cite

This paper shows accurate predictions for hover performance regardless of planform geometry, blade tip Mach number or disk loading. To prove this statement, sensitivity analyses were performed along with performance predictions for four rotor designs. Planform effects were also studied, such as blade anhedral, showing the strong sensitivity of the rotor blade performance due to geometric features. The steady state solution methodology with imposed Froude boundary conditions is shown to give accurate results for relatively coarse grid sizes. This approach leads to reduced computational costs compared to time-dependent simulations. It is also recognised that given the current accuracy of the available experimental data, the use of more advanced CFD methods may not be fully justified. To advance the accuracy of modern CFD methods a more comprehensive experimental dataset is required. Nomenclature AR = aspect ratio, R/c r e f a = speed of sound, m/s C p = pressure coefficient, (p − p ∞ )/(1/2ρ(Ωr/R) 2 ) C f = skin friction coefficient, τ w /(1/2ρ(Ωr/R) 2 ) C Q = torque coefficient, Q/( ρ(ΩR) 2 πR 3 ) C T = thrust coefficient, T/( ρ(ΩR) 2 πR 2 ) c = rotor chord, m E = endurance, s FoM = figure of merit, C 3/2 T /( √ 2C Q ) k = turbulent kinetic energy, m 2 /s 2 M = Mach number, V ∞ /a ∞ M tip = blade tip Mach number, ΩR/a ∞ * PhD Student, CFD Laboratory, School of Engineering.

show abstract

Section: Introductionmentioning

confidence: 99%

Validation of the Steady-State Hover Formulation for Accurate Performance Predictions

et al. 2019

View full text Add to dashboard Cite

show abstract

“…In the future, it would be useful to apply this to a specific aircraft at specific conditions, as previously demonstrated for the UH60-A aircraft [26].…”

Section: Flight Conditionsmentioning

confidence: 96%

“…The neural network method was selected due to its accuracy, robustness, and efficiency. More details of the ANN used and the effect of the number of layers, neurons, and outputs can be found in [25][26][27]. Kriging was also coded and used to compare, and produced similar results.…”

Section: B Optimizationmentioning

confidence: 99%

See 1 more Smart Citation

Optimizing Rotor Blades with Approximate British Experimental Rotor Programme Tips

Johnson

Barakos

2014

Journal of Aircraft

View full text Add to dashboard Cite

This work presents a framework for the optimization of certain aspects of a British Experimental Rotor Programme-like rotor blade in hover and forward flight so that maximum performance can be obtained from the blade. The proposed method employs a high-fidelity, efficient computational fluid dynamics technique that uses the harmonic balance method in conjunction with artificial neural networks as metamodels, and genetic algorithms for optimization. The approach has been previously demonstrated for the optimization of blade twist in hover and the optimization of rotor sections in forward flight, transonic aerofoils design, wing and rotor tip planforms. In this paper, a parameterization technique was devised for the British Experimental Rotor Programme-like rotor tip and its parameters were optimized for a forward flight case. A specific objective function was created using the initial computational fluid dynamics data and the metamodel was used for evaluating the objective function during the optimization using the genetic algorithms. The objective function was adapted to improve forward flight performance in terms of pitching moment and torque. 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 main computational cost was associated with the population of the genetic algorithms database necessary for the metamodel, especially because a full factorial method was used. The computational time of the optimization process itself, after the database has been obtained, is relatively insignificant. Therefore, the computational time was reduced with the use of the harmonic balance method as opposed to the time marching method. The novelty in this paper is twofold. Optimization methods so far have used simple aerodynamic models employing direct "calls" to the aerodynamic models within the optimization loops. Here, the optimization has been decoupled from the computational fluid dynamics data allowing the use of higher-fidelity computational fluid dynamics methods based on Navier-Stokes computational fluid dynamics. This allows a more realistic approach for more complex geometries such as the British Experimental Rotor Programme tip. In addition, the harmonic balance method has been used in the optimization process.

show abstract

“…The Neural Network method was selected due to its accuracy, robustness and efficiency. More details of the ANN used and the effect of the number of layers, neurons and outputs can be found in references [24][25][26] . Kriging was also coded and used to compare, and produced similar results.…”

Section: Introductionmentioning

confidence: 99%

Optimising Aspects of a BERP-like Rotor Using Frequency-Domain Methods

Johnson

Woodgate

Barakos

2013

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

Self Cite

View full text Add to dashboard Cite

This work presents a framework for the optimisation of certain aspects of a BERPlike rotor blade in forward flight while constraining hover performance. The proposed method employs a high-fidelity, efficient CFD technique that uses the Harmonic Balance method in conjunction with artificial neural networks (ANNs) as metamodels, and genetic algorithms (GAs) for optimisation. The approach has been previously demonstrated for the optimisation of linear twist of rotors in hover (steady case) and the optimisation of rotor sections in forward flight (unsteady case), transonic aerofoils, wing and rotor tip planforms.In this paper, a parameterisation technique was defined for the BERP-like rotor tip and three of the parameters were optimised in forward flight. A specific objective function was created using the initial CFD data and the metamodel was used for evaluating the objective function during the optimisation using the GAs. 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 were not sensitive to the employed techniques with substantial overlap between the outputs of the selected methods. The main CPU cost was associated with the population of the CFD database necessary for the metamodel using a full factorial method and even that was reduced with the use of the Harmonic Balance method.

show abstract

Optimisation of aspects of rotor blades in forward flight

Cited by 9 publications

References 32 publications

Validation of the Steady-State Hover Formulation for Accurate Performance Predictions

Validation of the Steady-State Hover Formulation for Accurate Performance Predictions

Optimizing Rotor Blades with Approximate British Experimental Rotor Programme Tips

Optimising Aspects of a BERP-like Rotor Using Frequency-Domain Methods

Contact Info

Product

Resources

About