Proposed Boundary Conditions for Gust-Airfoil Interaction Noise

Kim, Jae Wook; Lau, Alex Siu Hong; Sandham, Neil D.

doi:10.2514/1.j050428

Cited by 41 publications

(34 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…where the details of σ s (x) and λ s (x) can be found in Kim et al (2010). The turbulent velocity perturbation in Ω eddy is generated by taking the curl of a vector potential, i.e.…”

Section: Sponge Layer and Synthetic Inflow Turbulencementioning

confidence: 99%

On the reduction of aerofoil–turbulence interaction noise associated with wavy leading edges

2016

Self Cite

View full text Add to dashboard Cite

An aerofoil leading-edge profile based on wavy (sinusoidal) protuberances/tubercles is investigated to understand the mechanisms by which they are able to reduce the noise produced through the interaction with turbulent mean flow. Numerical simulations are performed for non-lifting flat-plate aerofoils with straight and wavy leading edges (denoted by SLE and WLE, respectively) subjected to impinging turbulence that is synthetically generated in the upstream zone (freestream Mach number of 0.24). Full threedimensional Euler (inviscid) solutions are computed for this study thereby eliminating self-noise components. A high-order accurate finite-difference method and artefact-free boundary conditions are used in the current simulations. Various statistical analysis methods, including frequency spectra, are implemented to aid the understanding of the noise-reduction mechanisms. It is found with WLEs, unlike the SLE, that the surface pressure fluctuations along the leading edge exhibit a significant source cut-off effect due to geometric obliqueness which leads to reduced levels of radiated sound pressure. It is also found that there exists a phase interference effect particularly prevalent between the peak and the hill centre of the WLE geometry, which contributes to the noise reduction in the mid-to high-frequency range.

show abstract

“…where the details of σ s (x) and λ s (x) can be found in Kim et al (2010). The turbulent velocity perturbation in Ω eddy is generated by taking the curl of a vector potential, i.e.…”

Section: Sponge Layer and Synthetic Inflow Turbulencementioning

confidence: 99%

On the reduction of aerofoil–turbulence interaction noise associated with wavy leading edges

2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…Simulations of this type have been performed by previous authors such as Gill et al 29,33 and Kim et al, 26 among others. The methodology of this case is now outlined.…”

Section: Vib Performance Of the Zonal Tcbc Methodsmentioning

confidence: 99%

“…Some authors, such as Kim et al 26 have used buffer zone profiles based upon cosine shapes as opposed to the polynomial function given in Equation 3. Both cosine and polynomial functions are tested in the current work.…”

Section: Iia Buffer Zone Dampingmentioning

confidence: 99%

See 1 more Smart Citation

Evaluation and Development of Non-Reflective Boundary Conditions for Aeroacoustic Simulations

Gill

Fattah

Zhang

2015

21st AIAA/CEAS Aeroacoustics Conference

View full text Add to dashboard Cite

The performance of several non-reflective acoustic boundary conditions is quantitatively compared using a plane wave test configuration. The study uses a high-order linearized Euler equation solver to find a non-reflective boundary condition which gives good performance in a variety of cases. The performance for acoustic waves with varying frequency and incident angle is compared in flows with varying Mach number. The performance of buffer zone, far-field, and characteristic non-reflective methods is compared. Some non-reflective boundary methods, such as buffer zones, contain tuneable parameters that are optimized in the current work. This provides a more comprehensive evaluation than previous studies which used constant values of the tuneable parameters. A new generic non-reflective zonal characteristic boundary condition is proposed and is shown to give improved performance in comparison to other tested methods. The performance of the proposed boundary condition is also demonstrated in a two-dimensional airfoil turbulence-interaction case that includes vortical waves leaving the domain, and in a three-dimensional duct mode case.

show abstract

“…In this paper, the latest SEM is combined with a sponge-layer technique [13][14][15] that was particularly designed for introducing velocity disturbances as well as absorbing spurious noise. With this combination, the level of spurious noise is kept sufficiently low to guarantee a clean sound field for CAA simulations.…”

Section: Introductionmentioning

confidence: 99%

An advanced synthetic eddy method for the computation of aerofoil–turbulence interaction noise

Kim

Haeri

2015

Journal of Computational Physics

Self Cite

View full text Add to dashboard Cite

Please cite this article in press as: J.W. Kim, S. Haeri, An advanced synthetic eddy method for the computation of aerofoil-turbulence interaction noise, J. Comput. Phys. (2015), http://dx.doi.org/10. 1016/j.jcp.2015.01.039 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractThis paper presents an advanced method to synthetically generate flow turbulence via an inflow boundary condition particularly designed for threedimensional aeroacoustic simulations. The proposed method is virtually free of spurious noise that might arise from the synthetic turbulence, which enables a direct calculation of propagated sound waves from the source mechanism. The present work stemmed from one of the latest outcomes of synthetic eddy method (SEM) derived from a well-defined vector potential function creating a divergence-free velocity field with correct convection speeds of eddies, which in theory suppresses pressure fluctuations. In this paper, a substantial extension of the SEM is introduced and systematically optimised to create a realistic turbulence field based on von Kármán velocity spectra. The optimized SEM is then combined with a well-established sponge-layer technique to quietly inject the turbulent eddies into the domain from the upstream boundary, which results in a sufficiently clean acoustic field. Major advantages in the present approach are: a) that genuinely three-dimensional turbulence is generated; b) that various ways of parametrisation can be created to control/characterise the randomly distributed eddies; and, c) that its numerical implementation is efficient as the size of domain section through which the turbulent eddies should be passing can be adjusted and minimised. The performance and reliability of the proposed SEM are demonstrated by a three-dimensional simulation of aerofoil-turbulence interaction noise.

show abstract

Proposed Boundary Conditions for Gust-Airfoil Interaction Noise

Cited by 41 publications

References 12 publications

On the reduction of aerofoil–turbulence interaction noise associated with wavy leading edges

On the reduction of aerofoil–turbulence interaction noise associated with wavy leading edges

Evaluation and Development of Non-Reflective Boundary Conditions for Aeroacoustic Simulations

An advanced synthetic eddy method for the computation of aerofoil–turbulence interaction noise

Contact Info

Product

Resources

About