Optimization of trailing-edge serrations with and without slits for broadband noise reduction

Kholodov, Pavel; Moreau, Stéphane

doi:10.1016/j.jsv.2020.115736

Cited by 22 publications

(9 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Section: Annual Power Generationmentioning

confidence: 99%

“…In our case, for all the considered cities, the wavelength factor has the highest impact on power generation. Indeed, the serration wavelength appears in different studies [45,63] as the main parameter for more noise reduction. Based on the results of Figure 8, the combination of wavelength level 2, amplitude level 3, and thickness level 2 is the optimum for this blade's performance through the Taguchi method.…”

Section: Annual Power Generationmentioning

confidence: 99%

See 1 more Smart Citation

Aerodynamic Optimization of Trailing-Edge-Serrations for a Wind Turbine Blade Using Taguchi Modified Additive Model

Qaissi¹,

Elsayed²,

Faqir³

et al. 2023

Energies

View full text Add to dashboard Cite

For the rotor, achieving relatively high aerodynamic performance in specific wind conditions is a long-term goal. Inspired by the remarkable flight characteristics of owls, an optimal trailing edge serration design is investigated and proposed for a wind turbine rotor blade. Fluid flow interaction with the proposed serrations is explored for different wind conditions. The result is supported by subsequent validation with three-dimensional numerical tools. The present work employs a statistical-numerical method to predict and optimize the shape of the serrations for maximum aerodynamic improvement. The optimal combination is found using the Taguchi method with three factors: Amplitude, wavelength, and serration thickness. The viability of the solution on an application is assessed using the Weibull distribution of wind in three selected regions. Results show that the presence of serration is capable of improving the annual power generation in all the investigated cities by up to 12%. The rated speed is also shifted from 10 m/s to 8 m/s for most configurations. Additionally, all configurations show similar trends for the instantaneous torque, where an increase is observed in pre-rated speed, whereas a decrease is noticed in the post-rated speed region. A look at the flow field pattern for the optimal design in comparison with the clean blade shows that the modified blade is able to generate more lift in the pre-stall region, while for the post-stall region, early separation and increased wake dominate the flow.

show abstract

Section: Annual Power Generationmentioning

confidence: 99%

Section: Annual Power Generationmentioning

confidence: 99%

Aerodynamic Optimization of Trailing-Edge-Serrations for a Wind Turbine Blade Using Taguchi Modified Additive Model

Qaissi¹,

Elsayed²,

Faqir³

et al. 2023

Energies

View full text Add to dashboard Cite

show abstract

“…Both experiments and numerical simulations show that TE serration is indeed an effective method of reducing TE noise. To use serrations in practical applications, however, reliable noise prediction models are essential because they are crucial in the design of optimal serration geometries (see for example a recent study by Kholodov & Moreau 2021). Howe (1991 a , b ) is among the earliest researchers to model the aerodynamic noise generated by serrated trailing edges analytically.…”

Section: Introductionmentioning

confidence: 99%

Analytical Green's function for the acoustic scattering by a flat plate with a serrated edge

Lyu

2023

J. Fluid Mech.

View full text Add to dashboard Cite

An analytical Green's function is developed to study the acoustic scattering by a flat plate with a serrated edge. The scattered pressure is solved using the Wiener–Hopf technique in conjunction with the adjoint technique. It is shown that the kernel decomposition proposed in recent literature appears only valid at high frequencies. We focus on this high-frequency regime and obtain the scattered pressure in the form of a contour integral. We show that such an integral, although complicated, can be evaluated exactly for any arbitrary piecewise linear serrations, for which closed-form analytical Green's functions are obtained. The derivation is validated by performing numerical integration of the contour integral showing excellent agreement. The Green's function is shown to agree well with the numerical results obtained using the finite element method at high frequencies. The noise directivity patterns are studied as a function of the frequency, serration amplitude, source position and Mach number. It is found that noise is often enhanced at low observer angles and may be slightly reduced at high observer angles, which may be understood from the perspective of an extended or removed rigid reflection surface. It is found that increasing the mean-flow Mach number leads to increasingly evident noise amplification at side angles, a seemingly strange Doppler behaviour exhibited in source-fixed coordinate frames. The analytical Green's function is applicable to both leading- and trailing-edge scatterings, and is particularly suitable for developing a three-dimensional trailing-edge noise model that is not only highly efficient but also capable of including non-frozen turbulence effects.

show abstract

“…New blade designs, such as active flow control, S-shape, tandem and counter-rotating, are under investigation (Biollo and Benini, 2013;Venturelli and Benini, 2016); however, these concepts are still immature. Researchers also focused on relevant issues including the effects of edge geometry (Liu et al, 2013) and noise (Moreau et al, 2019;Kholodov and Moreau, 2021).…”

Section: Introductionmentioning

confidence: 99%

An intellectual design case of compressor airfoils based on reinforcement learning

Xu,

Huang,

Zhang

et al. 2023

View full text Add to dashboard Cite

PurposeIn general, the existing compressor design methods require abundant knowledge and inspiration. The purpose of this study is to identify an intellectual design optimization method that enables a machine to learn how to design it.Design/methodology/approachThe airfoil design process was solved using the reinforcement learning (RL) method. An intellectual method based on a modified deep deterministic policy gradient (DDPG) algorithm was implemented. The new method was applied to agents to learn the design policy under dynamic constraints. The agents explored the design space with the help of a surrogate model and airfoil parameterization.FindingsThe agents successfully learned to design the airfoils. The loss coefficients of a controlled diffusion airfoil improved by 1.25% and 3.23% in the two- and four-dimensional design spaces, respectively. The agents successfully learned to design under various constraints. Additionally, the modified DDPG method was compared with a genetic algorithm optimizer, verifying that the former was one to two orders of magnitude faster in policy searching. The NACA65 airfoil was redesigned to verify the generalization.Originality/valueIt is feasible to consider the compressor design as an RL problem. Trained agents can determine and record the design policy and adapt it to different initiations and dynamic constraints. More intelligence is demonstrated than when traditional optimization methods are used. This methodology represents a new, small step toward the intelligent design of compressors.

show abstract

Optimization of trailing-edge serrations with and without slits for broadband noise reduction

Cited by 22 publications

References 28 publications

Aerodynamic Optimization of Trailing-Edge-Serrations for a Wind Turbine Blade Using Taguchi Modified Additive Model

Aerodynamic Optimization of Trailing-Edge-Serrations for a Wind Turbine Blade Using Taguchi Modified Additive Model

Analytical Green's function for the acoustic scattering by a flat plate with a serrated edge

An intellectual design case of compressor airfoils based on reinforcement learning

Contact Info

Product

Resources

About