Far Field Noise Prediction by Large Eddy Simulation and Ffowcs Williams Hawkings Analogy

Magagnato, Franco; Sorgüven, Esra; Gabi, Martin

doi:10.2514/6.2003-3206

Cited by 47 publications

(8 citation statements)

References 5 publications

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“…Casalino, Jacob & Roger 2003;Jacob et al 2005), the large eddy simulation method (LES) (e.g. Casalino et al 2003;Magagnato, Sorgüven & Gabi 2003;Boudet et al 2005;Jacob et al 2005;Greschner et al 2008;Agrawal & Sharma 2014;Giret et al 2015) and the detached eddy simulation method (DES) (e.g. Creschner et al 2004;Caraeni et al 2007;Gerolymos & Vallet 2007;Greschner et al 2008).…”

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confidence: 99%

Numerical investigation on body-wake flow interaction over rod–airfoil configuration

et al. 2015

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Numerical investigations of body-wake interactions were carried out by simulating the flow over a rod-airfoil configuration using high-order implicit large eddy simulation (HILES) for the incoming velocity U ∞ = 72 m s −1 and a Reynolds number based on the airfoil chord 4.8 × 10 5 . The flow over five different rod-airfoil configurations with different distances of L/d = 2, 4, 6, 8 and 10, respectively, were calculated for the analysis of body-wake interaction phenomena. Various fundamental mechanisms dictating the intricate flow phenomena including force varying regulation, flow structures and flow patterns in the interaction region, turbulent fluctuations and their suppression, noise radiation and fluid resonant oscillation, have been studied systematically. Due to the airfoil downstream, a relatively higher base pressure is exerted on the surface of the cylinder upstream, and the pressure fluctuation on the surface of the rod-airfoil configuration with L/d = 2 is significantly suppressed, resulting in a reduction of the fluctuating lift. Following the distance between the cylinder and airfoil strongly decreases, Kármán-street shedding is suppressed due to the blocking effect. The flow in this interaction region has two opposite tendencies: the influence of the airfoil on the steady flow is to accelerate it and the counter-rotating vortices connecting with the leading edge of the airfoil tend to slow the flow down. There may be two flow patterns associated with the interference region, i.e. the Kármán-street suppressing mode and the Kármán-street shedding mode. The primary vortex shedding behind the cylinder upstream, and the shedding wake impingement onto the airfoil downstream, play a dominant role in the production of turbulent fluctuations. When primary vortex shedding is suppressed, the intensity of impingement is weakened, resulting in a significant suppression of the turbulent fluctuations. Due to these factors, a special broadband noise without a manifestly distinguishable peak is radiated by the rod-airfoil configuration with L/d = 2. The fluid resonant oscillation within the flow interaction between the turbulent wake and the bodies was further investigated by adopting a feedback model, which confirmed that the effect of fluid resonant oscillation becomes stronger when L/d = 6 and 10.The results obtained in this study provide physical insight into the understanding of the mechanisms relevant to the body-wake interaction.

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Numerical investigation on body-wake flow interaction over rod–airfoil configuration

et al. 2015

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“…Since sound generation and propagation are included in the compressive Navier-Stokes equation, high-resolution transient CFD simulation is required before performing CAA. In this study, the unsteady flow of turbulence was treated using large eddy simulation (LES), which is commonly used in the preceding computational aeroacoustics analysis [21][22][23]. In addition, a coupled solver was used to combine density-based solver and pressure-based solver.…”

Section: Numerical Analysismentioning

confidence: 99%

Noise Reduction of an Extinguishing Nozzle Using the Response Surface Method

et al. 2019

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An inert gas such as nitrogen is used as an extinguishing agent to suppress unexpected fire in places such as computer rooms and server rooms. The gas released with high pressure causes noise above 130 dB. According to recent studies, loud noise above 120 dB has a strong vibrational energy that leads to a negative influence on electronic equipment with a high degree of integration. In this study, a basic fire-extinguishing nozzle with absorbent was selected as the reference model, and numerical analysis was conducted using the commercial software, ANSYS FLUENT ver. 18.1. A total of 45 experiment points was selected using the design of experiment (DOE) method. An optimum point was derived using the response surface method (RSM). Results show that the vibrational energy of the noise was reduced by minimizing the turbulence kinetic energy. Pressure and velocity distributions were calculated and graphically depicted with various absorbent configurations.

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“…Casalino et al (2003) developed an aeroacoustic code based on porous Ffows-Williams and Hawking (FW-H) in combination with unsteady RANS simulations for the acoustic prediction. In a similar manner, Magagnato et al (2003), Sorguven et al (2003) and Boudet et al (2005) coupled a FW-H acoustic analogy with LES calculations which allowed capturing of the sub-Karman vortical structures responsible for noise emission at higher frequencies. Greschner et al (2008) combined a detached eddy simulation (DES) with the FW-H analogy to evaluate far-field pressure spectra.…”

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confidence: 99%

Experimental study of vortex–structure interaction noise radiated from rod–airfoil configurations

Wang

Chen

et al. 2014

Journal of Fluids and Structures

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Far Field Noise Prediction by Large Eddy Simulation and Ffowcs Williams Hawkings Analogy

Cited by 47 publications

References 5 publications

Numerical investigation on body-wake flow interaction over rod–airfoil configuration

Numerical investigation on body-wake flow interaction over rod–airfoil configuration

Noise Reduction of an Extinguishing Nozzle Using the Response Surface Method

Experimental study of vortex–structure interaction noise radiated from rod–airfoil configurations

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