Implementation of a FWH approach in a high-order LES tool for aeroacoustic noise predictions

Alhawwary, Mohammad A.; Wang, Zhi Jian

doi:10.2514/6.2020-1724

Cited by 11 publications

(3 citation statements)

References 59 publications

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“…For the far-field noise predictions, methods such as Ffowcs Williams-Hawkings (FW-H), Acoustic Perturbation Equations (APE), Lighthill's analogies and Direct Noise Computation (DNC) are commonly used for predicting and mitigating the induced noise from side-view mirrors. [29][30][31][32][33] Lokhande et al 34 used the LES approach with the FW-H analogy and DNC method for evaluating acoustic and compared the numerical prediction against the experimental by Siegert et al 13 The hydrodynamic pressure fluctuations were resolved accurately up to 700 Hz with a maximum deviation of 5-10 dB, and also SPL reported was in reasonable agreement with experiments at high frequencies against the experimental results of Siegert et al 13 Rung et al 14 observed a similar deviation in the SPL level predicted by DES with the FW-H analogy. The authors point out that the deviations in the studies mentioned above were attributed to the low-resolution of the grid in the wake and larger time steps used.…”

Section: A the Generic Side View Mirrormentioning

confidence: 99%

Noise emitted from a generic side-view mirror with different aspect ratios and inclinations

2021

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Noise radiated from flow past different configurations of the Half-Round Mirror (HRM) mounted on a plate has been investigated using computational aeroacoustics (CAA).The Stress-Blended Eddy Simulation (SBES), together with the Ffowcs Williams-Hawkings (FW-H) acoustic analogy, was employed to predict near field flow and far-field noise, respectively. The numerical methodology was verified and validated for the standard HRM case against several previously published numerical and experimental data sets, which provides good agreement. Further, (i) the choice of different type of grids for CAA and (ii) the applicability of methods such as the Kirchhoff integral and the FW-H using near field inputs computed from the SBES were assessed. As a next step, the effect of induced noise from the HRM for different a) Aspect Ratios (AR) ranging from 1 to 2.5 and b) inclination of the mirror towards the plate (θ) ranging from 0° to 32° were investigated. For all the investigated cases, the distribution of the radiated noise exhibits a dipole-like structure closer to the plate and a monopole-like structure away from the plate. By inclining the mirror closer to the mounting plate, the emitted noise is reduced both in the vertical and lateral directions of the wake, whereas an increase in the AR of the mirror increases the induced noise considerably. The findings from the current study can provide a deeper understanding for effectively mitigating the induced aerodynamic noise from side-view mirrors.

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Section: A the Generic Side View Mirrormentioning

confidence: 99%

Noise emitted from a generic side-view mirror with different aspect ratios and inclinations

2021

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“…The Ffowcs Williams-Hawkings (FWH) analogy provides the possibility of using computational aeroacoustics for most industrial applications, as it can predict the sound generated by moving surfaces, such as helicopter blades [21] or car wheels. In the particular case of the aeroacoustic noise from bluff bodies, the FWH analogy has been used either with low-Mach cases, as in the work by Cianferra et al [22], Yao et al [23] and Khalighi et al [24]; transient flows, as in the study by Cai et al [25]; or highly compressible environments (i.e., high subsonic or supersonic Mach numbers), as in the work by Alhawwary and Wang [26], Shur et al [27], Morris et al [28] and Uzun et al [29].…”

Section: Introductionmentioning

confidence: 99%

Hybrid Computation of the Aerodynamic Noise Radiated by the Wake of a Subsonic Cylinder

Eiximeno,

Tur-Mongé,

Lehmkuhl

et al. 2023

Fluids

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The noise radiated by the flow around a cylinder in the subcritical regime at ReD=1×104 and at a subsonic Mach number of M=0.5 is here studied. The aerodynamic sound radiated by a cylinder has been studied with a wide range of Reynolds numbers, but there are no studies about how the Mach number affects the acoustic field in the subsonic regime. The flow field is resolved by means of large-eddy simulations of the compressible Navier–Stokes equations. For the study of the noise propagation, formulation 1C of the Ffowcs Williams–Hawkings analogy is used. The fluid flow results show good agreement when comparing the surface pressure coefficient, the recirculation length, the vortex shedding frequency and the force coefficients against other studies performed under similar conditions. The dynamic mode decomposition of the pressure fluctuations is used to relate them with the far-field noise. It is shown that, in contrast to what happens for low Mach numbers, quadrupoles have a significant impact mainly in the observers located in the streamwise direction. This effect leads to a global monopole directivity pattern as the shear fluctuations compensate for the lower value of the aeolian tone away from the cross-stream direction.

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“…Despite this, relatively few studies to date have used the DG method, or similar high-order methods, such as the flux reconstruction method [25], to study jet noise, see e.g. [12,13,26,27]. Instead, finite volume and finite difference methods are predominantly used, see e.g.…”

Section: Introductionmentioning

confidence: 99%

Aeroacoustic Analysis of a Closely Installed Chevron Nozzle Jet using the High-Order Discontinuous Galerkin Method

Lindblad

Sherwin

Cantwell

et al. 2023

AIAA AVIATION 2023 Forum

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In this paper, we use Large Eddy Simulations (LES) in combination with the Ffowcs Williams -Hawkings method to study the influence of chevrons on the flow field as well as the noise produced by a closely installed M = 0.6 jet. The LES simulations are performed with the spectral/hp element framework Nektar++ (www.nektar.info). Nektar++ uses the high-order discontinuous Galerkin method and an implicit scheme based on the matrix-free Newton-GMRES method to discretize the unfiltered Navier-Stokes equations in space and time, respectively. The far-field noise is computed using Antares (www.cerfacs.fr/antares/). Antares solves the Ffowcs Williams -Hawkings equation for a permeable integration surface in the time-domain using a source-time dominant algorithm. The aerodynamic results show good agreement with experimental data obtained in the Doak Laboratory Flight Jet Rig, located at the University of Southampton. Some discrepancies are observed in terms of the far-field noise levels, especially for higher polar observer angles relative to the downstream jet axis. In terms of noise reduction potential, the simulations predict that the chevrons reduce the OASPL by 1dB compared to an installed round nozzle for all observers located on the unshielded side of the wing. This should be compared to the experiments, which predict a 1.5dB noise reduction for the same chevron nozzle.

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Implementation of a FWH approach in a high-order LES tool for aeroacoustic noise predictions

Cited by 11 publications

References 59 publications

Noise emitted from a generic side-view mirror with different aspect ratios and inclinations

Noise emitted from a generic side-view mirror with different aspect ratios and inclinations

Hybrid Computation of the Aerodynamic Noise Radiated by the Wake of a Subsonic Cylinder

Aeroacoustic Analysis of a Closely Installed Chevron Nozzle Jet using the High-Order Discontinuous Galerkin Method

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