Large Eddy simulation of cross-flow around a square rod at incidence with application to tonal noise prediction

Mueller, Andreas

doi:10.3990/1.9789036532853

Cited by 2 publications

(2 citation statements)

References 39 publications

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“…For the objectives of this study, the area circled in Figure 9 (corresponding more or less to the [220,320] Hz interval) is particularly relevant as regards the comparison between simulations and experiment: on the numerical side, the vortex shedding frequency is clearly visible; on the experimental side, a more complex pattern of peaks is present. Recall that a vortex shedding frequency of the order of 270 Hz is plausible for the system of interest, as suggested in [26] where the shedding frequency is computed of a square cylinder (200 mm each side) with 45° of incidence at a Reynolds number of 5.5·10 4 . These results motivate a deeper investigation of the experimental signal and this is done by windowing it through the Welch filter technique [27] for a transient analysis aimed at studying the evolution of the most energetic frequencies.…”

Section: The Resultsmentioning

confidence: 99%

Diagnosis of vortex induced vibration of a gravity damper

Scappaticci¹,

Castellani²,

Astolfi³

et al. 2018

Diagnostyka

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A gravity damper is a one-way valve, employed for regulating the airflow rate in ducts, generally constituted by a series of rectangular panels (closure sections), connected to an articulated quadrilateral synchronizing the movements. If the device needs to process large masses of high speed air, as common in the case of energy conversion systems, disadvantageous dynamic effects can occur. In this study, vortexinduced vibration (VIV), occurring on a gravity damper for high values of the Reynolds number, is investigated. The analysis of this work couples numerical methods (Computational Fluid Dynamics with Large-Eddy Simulation turbulence model and Finite Element Method) to experiments: a full-scale accelerometric measurement campaign is actually performed at the wind tunnel facilities of the University of Perugia. VIVs are diagnosed and quantified through the experimental vibration analysis, which is interpreted through numerical simulations. The large amplitude of VIV is interpreted as due to a tendency towards lockin because of the approaching of the vortex shedding frequency to a natural vibration mode of the system. The integrated numerical and experimental framework finally inspires two different design solutions for mitigating the amplitude of VIV: these strategies are tested at the wind tunnel and they are indeed shown to be effective.

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Section: The Resultsmentioning

confidence: 99%

Diagnosis of vortex induced vibration of a gravity damper

Scappaticci¹,

Castellani²,

Astolfi³

et al. 2018

Diagnostyka

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“…However, the majority of studies on this field focused on circular cross-sections [2]. Concerning rectangular cross-sections, experimental studies have shown variations in the wake properties due to geometrical characteristics, making parameters such as the aspect ratio [3], the incidence angle [4][5][6], and the sharpness [7] crucial in the flow analysis. Specifically, the contribution of the drag dipole is enhanced compared to circular cylinder, and the separation points are fixed on corners.…”

Section: Introductionmentioning

confidence: 99%

Effect of the incidence angle of the flow on the acoustic dipolar radiation of rectangular cylinders

Chiocchetti,

Marx,

Margnat

et al. 2022

Proceedings of the 10th Convention of the European Acoustics Association Forum Acusticum 2023

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This study focuses on the noise produced by cylinder-flow interactions. The aerodynamic noise is established when the instabilities in the shear layer lead to periodic vortex shedding. This results in a tonal noise called "aeolian tone". For a rectangular cylinder with no incidence, the sources of noise are located along the spanwise direction. They have a dipolar directivity, orthogonal to the flow. However, when the incidence of the flow varies, the orientation of the dipoles changes. This phenomenon is investigated experimentally in the test section of an anechoic wind-tunnel, with an array of microphones placed orthogonally to the cylinder. The rectangular cylinders studied have two different aspect ratios: AR=1 and AR=2, for Reynolds numbers between 2 000 and 23 000. A beamformingbased method is used to recover the dipolar angles from the microphones data. For the two cylinders, the dipole tilts similarly when changing the flow incidence angle. These results confirm numerical predictions of the sound directivity based on Curle's solution, for a compact source using the drag and lift force fluctuations.

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Large Eddy simulation of cross-flow around a square rod at incidence with application to tonal noise prediction

Cited by 2 publications

References 39 publications

Diagnosis of vortex induced vibration of a gravity damper

Diagnosis of vortex induced vibration of a gravity damper

Effect of the incidence angle of the flow on the acoustic dipolar radiation of rectangular cylinders

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