Mathematical and Numerical Modeling of Turbulent Flows

Vedovoto, João Marcelo; Serfaty, Ricardo; Neto, Aristeu da Silveira

doi:10.1590/0001-3765201520140510

Cited by 10 publications

(5 citation statements)

References 27 publications

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“…The interpolation function projects the physical field from the Cartesian grid to the IB points, whereas the distribution function maps the physical field from the IB points back to the Cartesian grid. The original interpolation and distribution interaction function between the immersed boundary and the fluid for the multidirect forcing method can be found in [30,34].…”

Section: A Directional Version Of the Multi-direct Forcing Methodsmentioning

confidence: 99%

Assessment of two immersed boundary methods for flow over thin plates and sharp edges

Andrade

Martins

Neto

et al. 2018

J Braz. Soc. Mech. Sci. Eng.

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The extension of two different immersed boundary methods is proposed and applied to the numerical computation of uniform flow over blunt and sharp bodies: a directional version of the multi-direct forcing method and a semi-implicit version of the local ghost cell method; the first is an indirect and the second a direct method. These methods are investigated by applying them to incompressible laminar flows. The salient features of the methods are described with special emphasis on the ability to compute flows past thin plates and sharp edges. The transport equations are discretized by using the finite difference method in a Cartesian grid. The immersed boundary is represented by a finite number of Lagrangian points distributed over the solid-fluid interface. In order to test the accuracy of these approaches, three different benchmark cases are assessed. The directional version of the multi-direct forcing method is in good accordance with the flow past blunt bodies. However, it shows some numerical inconsistency when dealing with sharp and thin geometries due to the discontinuity present in the velocity and pressure fields. On the other hand, the semi-implicit version of the local ghost cell method presents good agreement with analytical, numerical and experimental data of all simulated cases. Keywords Immersed boundary method Á Ghost cell method Á Multi-direct forcing method Á Cartesian grid Á Thin plate Á Sharp geometry edges

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Section: A Directional Version Of the Multi-direct Forcing Methodsmentioning

confidence: 99%

Assessment of two immersed boundary methods for flow over thin plates and sharp edges

Andrade

Martins

Neto

et al. 2018

J Braz. Soc. Mech. Sci. Eng.

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“…where n 1 is the normal distance from the viscous wall units and A 1 is a constant, usually taken as 25 (Vedovoto et al, 2015). In OpenFOAM LES, the filtering between the larger turbulence scales that have to be directly resolved by N-S equations and the smaller scales modelled by SGS model were achieved using equations ( 3) and (4), in which D is the filter width and defined as the cube root of cell volume.…”

Section: Methodsmentioning

confidence: 99%

Large eddy simulation of airfoil self-noise using OpenFOAM

Jawahar¹,

Lin²,

Savill

2018

AEAT

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Purpose-The purpose of this paper is to investigate airfoil self-noise generation and propagation by employing a hybrid method based on the Large-eddy simulation (LES) approach and Curle's acoustic analogy as implemented in OpenFOAM. Design/methodology/approach-Large-eddy simulation of near-field flow over a NACA6512-63 airfoil at zero angle of attack with a boundary layer trip at Re = 1.9 × 10 5 has been carried out using the OpenFOAM ® CFD code. Calculated flow results are compared with published experimental data. The LES includes the wind-tunnel installation effects by using appropriate inflow boundary conditions obtained from a RANS ݇ − ߱ ܵܵܶ model computation of the whole wind tunnel domain. Far-field noise prediction was achieved by an integral method based on Curle's acoustic analogy. The predicted sound pressure levels are validated against the experimental data at various frequency ranges. Findings-The numerical results presented in this paper show that the flow features around a NACA6512-63 airfoil have been correctly captured in OpenFOAM LES calculations. The mean surface pressure distributions and the local pressure peaks for the step-trip setup agree very well with the experimental measurements. Aeroacoustic prediction using Curle's analogy shows an overall agreement with the experimental data. The Sound Pressure Level (SPL)-frequency spectral analysis produces very similar data at low to medium frequency, whereas the experimentally observed levels are slightly overpredicted at a higher frequency range. Practical implications-This study has achieved and evaluated an alternative aeroacoustic simulation method based on the combination of LES with a simple Smagorinsky SGS model and Curle's analogy, as implemented in the OpenFOAM CFD code. The unsteady velocity/pressure source data produced can be used for any simpler analytically-based far-field noise prediction scheme. Originality/value-A complete integration of the LES and Curle's acoustic analogy for aeroacoustic simulations has been achieved in OpenFOAM. The capability and accuracy of the hybrid method are fully evaluated for high-camber airfoil selfnoise predictions. Wind-tunnel installation effects have been incorporated properly into the LES.

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“…. 25 Figura -Pressão média no escoamento interno ao rotor de uma turbina industrial (VEDOVOTO et al, 2015) Figura -Definição dos volumes e pontos de velocidade ativos e inativos. Pontos ativos de pressão ; pontos inativos de pressão , pontos ativos de velocidade Ì e pontos inativos de velocidade j (BERTHELSEN;FALTINSEN, 2007).…”

Section: Lista De Ilustraçõesunclassified

“…Além disso, esse método pode conter considerável perda de qualidade caso a geometria envolvida seja fortemente irregular (VERZICCO et al, 2000). Outra possível solução, já bastante conhecida academicamente Figura 2 -Pressão média no escoamento interno ao rotor de uma turbina industrial (VEDOVOTO et al, 2015).…”

Section: Introductionunclassified

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Métodos de fronteira imersa para corpos esbeltos: implementação e validação

Andrade¹

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Mathematical and Numerical Modeling of Turbulent Flows

Cited by 10 publications

References 27 publications

Assessment of two immersed boundary methods for flow over thin plates and sharp edges

Assessment of two immersed boundary methods for flow over thin plates and sharp edges

Large eddy simulation of airfoil self-noise using OpenFOAM

Métodos de fronteira imersa para corpos esbeltos: implementação e validação

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