Large-eddy simulation of circular cylinder flow at subcritical Reynolds number: Turbulent wake and sound radiation

Guo, Li; Zhang, Xing; He, Guowei

doi:10.1007/s10409-015-0528-0

Cited by 15 publications

(4 citation statements)

References 25 publications

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“…24. However, these observations are different from the findings in flows past a circular cylinder, [28][29][30] where the loading noise showing a dipole pattern is predominant. These differences can be explained based on the formation and location of the powerful noise sources.…”

Section: B Noise Fieldcontrasting

confidence: 96%

Noise radiated by low-Reynolds number flows past a hemisphere at Ma = 0.3

2017

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Flows past a hemisphere and their noise generation are investigated at the Reynolds numbers (Re) of 1000 and 5000. The Mach number is 0.3. The computational method of the flows is large eddy simulation. The noise is computed using the Ffowcs Williams and Hawkings Formulation 1C (F1C). An integral surface with an open end is defined for the F1C. The end surface is removed to reduce the numerical contamination that is introduced by vortices passing this surface. However, the contamination cannot be completely reduced since a discontinuity of the flow quantities still exists at the open surface boundary. This problem is solved using a surface correction method, in which a buffer zone is set up at the end of the integral surface. The transformation of flow structures due to Re is explored. Large coherent structures are observable at low Re, whereas they diminish at high Re. A large amount of small-scale turbulent vortices occur in the latter case. It is found that these characteristics of the flows have an important influence on the noise generation in regard to the noise spectra. In the flows studied in this work, the fluctuating pressure on the walls is a negligible noise contributor as compared with the wake.

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Section: B Noise Fieldcontrasting

confidence: 96%

Noise radiated by low-Reynolds number flows past a hemisphere at Ma = 0.3

2017

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“…The LES simulations are able to capture the flow noise sources with great detail over a wide range of frequencies, and this leads to accurate acoustic predictions. There is voluminous literature describing numerical studies on sound generated by turbulent flow past a circular cylinder using hybrid LES-acoustic analogy approaches (for example, see [1][2][3][4][5], although the list is by no means exhaustive). Seo and Moon [1] presented a technique to predict the flow-induced noise generated by long span bodies and examined a cylinder immersed in low-Mach-number flow.…”

Section: Nomenclaturementioning

confidence: 99%

“…A compressible unstructured LES solver was coupled with the Ffowcs Williams and Hawkings acoustic analogy to predict aerodynamic noise from a rod-airfoil configuration [3]. Guo et al [4] simulated flow past a circular cylinder using the LES in conjunction with the Vreman's subgrid-scale model to calculate the subgrid stresses. The far-field acoustic pressure was then predicted using Curle's integral of Lighthill's acoustic analogy.…”

Section: Nomenclaturementioning

confidence: 99%

Acoustic Scattering for Rotational and Translational Symmetric Structures in Nonuniform Potential Flow

et al. 2017

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An efficient approach is proposed to predict acoustic scattering with nonuniform potential flow effects for structures with rotational and translational symmetries. The convected wave equation is transformed to Helmholtz and Laplace equations using a time transformation. The boundary-element method is used to formulate scattering by rotationally symmetric structures as two separate block circulant matrix equations and, similarly, as two separate block Toeplitz matrix equations for structures with translational symmetry. Discrete Fourier transform is employed to solve the block circulant systems. The block Toeplitz systems are solved using the generalized minimal residual method along with the discrete Fourier transform. Solving the convected wave equation using structured matrices significantly reduces computational time and storage requirements. To demonstrate the application of the formulation, two exterior acoustic case studies are considered. The first case study examines acoustic scattering from a sphere submerged in potential flow under monopole source excitation. Directivity plots obtained using the proposed technique are compared with analytical results. The second case study examines flow-induced noise generated by a rigid cylinder immersed in low-Mach-number flow, with the effect of mean flow on the scattered acoustic field taken into account using nonuniform potential flow. The fluctuating flowfield is obtained using an incompressible computational fluid dynamics solver. Acoustic sources based on Lighthill's analogy are extracted from the flowfield data using a high-order reconstruction scheme. Results from the hybrid computational fluid dynamics-boundaryelement method technique are presented for turbulent flow past the cylinder, with Reynolds number based on cylinder diameter of Re D 46;000 and Mach number M 0.21. The aeroacoustic results are compared with data from literature.

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“…5 Therefore, the numerical computation of aerodynamic and aeroacoustic characteristics of bluff bodies (mainly circular cylinders) have received extensive attention. [6][7][8][9][10][11][12][13][14][15] In this paper, we shall concentrate on a passive flow control method [16][17][18][19][20][21][22][23] using wavy circular cylinders for reducing the aerodynamic drag and aeroacoustic sound.…”

Section: Introductionmentioning

confidence: 99%

Optimization of wavy cylinder for aerodynamic drag and aeroacoustic sound reduction using computational fluid dynamics analysis

Karthik

Jeyakumar

Sebastin

2020

Proceedings of the Institution of Mechanical Engineers, Part C:

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Motivated by the requirement to lessen the aerodynamic drag and aeroacoustic sound of the bluff bodies, the present paper is devoted to a numerical analysis of the aerodynamics and aeroacoustics related with the flow past wavy circular cylinders. Based on the efficient flow control method, as has been presented by preceding researchers, the existing work embarks upon an investigation on the wavy cylinder at a various wavelength and amplitude conditions. Computations are performed for a circular cylinder of the length-to-diameter ratio ( L/ D) of 25 at a Reynolds number ( Re) of 97300 using large eddy simulation and Ffowcs Williams- Hawking’s acoustic analogy. Firstly, the cylinder without waviness is subjected to a uniform incoming flow is considered for validation against measurements. Secondly, various collection of wave shape parameters, specifically dimensionless wavelength λ/ D (=1 to 2.5), and wave amplitude a/ D (=0.05 to 0.2) have been taken into consideration. It is disclosed that the proper selection of shape parameters could significantly reduce the drag and sound emission levels, compared to the normal cylinder. Finally, a multi-objective particle swarm optimization was performed using the radial basis neural network to simultaneously reduce the aerodynamic drag and sound emission, with λ/ D and a/ D as design variables. We recognized a critical λ/ D and a/ D for the wavy circular cylinder at the considered subcritical Re.

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Large-eddy simulation of circular cylinder flow at subcritical Reynolds number: Turbulent wake and sound radiation

Cited by 15 publications

References 25 publications

Noise radiated by low-Reynolds number flows past a hemisphere at Ma = 0.3

Noise radiated by low-Reynolds number flows past a hemisphere at Ma = 0.3

Acoustic Scattering for Rotational and Translational Symmetric Structures in Nonuniform Potential Flow

Optimization of wavy cylinder for aerodynamic drag and aeroacoustic sound reduction using computational fluid dynamics analysis

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