A Versatile Implementation of Acoustic Analogy Based Noise Prediction Method in a General-Purpose CFD Code

Kim, Sang Hoon; Dai, Yi; Koutsavdis, Evangelos; Sovani, Sandeep; Kadam, Nitin N.; Ravuri, Krishna

doi:10.2514/6.2003-3202

Cited by 18 publications

(14 citation statements)

References 11 publications

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“…This calculation was performed using the Ffowcs Williams-Hawkins acoustic analogy (FW-H) [12] recently implemented in Fluent 6.1. Kim et al [16] have provided an in-depth description regarding the implementation of this analogy. The FW-H acoustic analogy is applicable if the speed of flow is low, the noise due to viscous and turbulent stresses is negligible compared to that due to pressure, and the receiver is located outside of the source regions.…”

Section: Acoustic Analogy Approachmentioning

confidence: 99%

Computational aero-acoustic analysis of a passenger car with a rear spoiler

Tsai

Tai

et al. 2009

Applied Mathematical Modelling

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a b s t r a c tThis study proposes an effective numerical model based on the Computational Fluid Dynamics (CFD) approach to obtain the flow structure around a passenger car with wing type rear spoiler. The topology of the test vehicle and grid system is constructed by a commercial package, ICEM/CFD. FLUENT is the CFD solver employed in this study. After numerical iterations are completed, the aerodynamic data and detailed complicated flow structure are visualized using commercial packages, Field View and Tecplot. The wind effect on the aerodynamic behavior of a passenger car with and without a rear spoiler and endplate is numerically investigated in the present study. It is found that the installation of a spoiler with an appropriate angle of attack can reduce the aerodynamic lift coefficient. Furthermore, the installation of an endplate can reduce the noise behind the car. It is clear that the vertical stability of a passenger car and its noise elimination can be improved. Finally, the aerodynamics and aero-acoustics of the most suitable design of spoiler is introduced and analyzed.

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Section: Acoustic Analogy Approachmentioning

confidence: 99%

Computational aero-acoustic analysis of a passenger car with a rear spoiler

Tsai

Tai

et al. 2009

Applied Mathematical Modelling

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“…FLUENT is a finite-volume solver and the temporal and spatial discretisation schemes available in it provide at most second-order accuracy in space and time. Many studies (22,23) have shown FLUENT to be capable of simulating unsteady flow problems, and of resolving the flow structures responsible for noise generation when suitably designed computational mesh and time-step sizes are used. Options for both explicit as well as the implicit time-stepping are available with the solver.…”

Section: Computed Resultsmentioning

confidence: 99%

Computational investigation of cavity flow control using a passive device

Khanal

Knowles

Saddington

2012

Aeronaut. j. (1968)

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In this paper, flow control effectiveness of a passive device in relation to open cavity flowfield is investigated computationally and compared with experimental work. Specifically the modification in the cavity flowfield due to the presence of a spoiler is studied in details to explain the physics behind the flow control effects. A combination of 2D and 3D flow visualisation tools are used to understand the flow behaviour inside the cavity and the quantitative analysis of the unsteady pressure fluctuations is also performed to assess the unsteady effects. Flow simulations with a turbulence model based on a hybrid RANS/LES (commonly known as Detached-Eddy Simulation (DES)) are used in this study. The time-mean flow visualisation clearly showed the presence of three dimensional effects inside the empty cavity whereas the 3D effects were found to diminish in the presence of a spoiler. In the unsteady flow analysis, near-field acoustic spectra were computed for empty cavity as well as cavity-with-spoiler cases. Study of unsteady pressure spectra for the cavity-with-spoiler case was found to record the complete suppression of the dominant tones in the presence of the spoiler. The analysis has indicated that the main reason behind this suppression is due to the inability of faintly energised vortical structures (faintly energised as a result of the extraction of turbulent kinetic energy by the spoiler) to maintain the unsteady flapping of the separated shear layer.

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“…It is often the case that the flow is computed with a two-dimensional cavity model, such as reference [4] (Rowley, et al, 2002) and reference [23] (Sung-Eun Kim, et al, 2003). For two-dimensional CFD models on which the FH-W integrals are to be evaluated, the current implementation allows users to specify what can be called a "correlation-length   c L " over which the flow is assumed to be perfectly correlated.…”

Section: Acoustic Wave Propagation S Smentioning

confidence: 99%

Analysis on Physical Mechanism of Sound Generation inside Cavities Based on Acoustic Analogy Method

Yang¹,

Li²,

Li³

et al. 2013

OJFD

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Analysis of coupling aerodynamics and acoustics are performed to investigate the self-sustained oscillation and aerodynamic noise in two-dimensional flow past a cavity with length to depth ratio of 2 at subsonic speeds. The large eddy simulation (LES) equations and integral formulation of Ffowcs-Williams and Hawings (FW-H) are solved for the cavity with same conditions as experiments. The obtained density-field agrees well with Krishnamurty's experimental schlieren photograph, which simulates flow-field distributions and the direction of sound wave radiation. The simulated self-sustained oscillation modes inside the cavity agree with Rossiter's and Heller's predicated results, which indicate frequency characteristics are obtained. Moreover, the results indicate that the feedback mechanism that new sheddingvortexes induced by propagation of sound wave created by the impingement of the shedding-vortexes in the shear-layer and rear cavity face leads to self-sustained oscillation and high noise inside the cavity. The peak acoustic pressure occurs in the first oscillation mode and the most of sound energy focuses on the low-frequency region.

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A Versatile Implementation of Acoustic Analogy Based Noise Prediction Method in a General-Purpose CFD Code

Cited by 18 publications

References 11 publications

Computational aero-acoustic analysis of a passenger car with a rear spoiler

Computational aero-acoustic analysis of a passenger car with a rear spoiler

Computational investigation of cavity flow control using a passive device

Analysis on Physical Mechanism of Sound Generation inside Cavities Based on Acoustic Analogy Method

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