Direct numerical simulation of flow over a forward-facing step – Flow structure and aeroacoustic source regions

Scheit, Christoph; Esmaeili, Arash; Becker, Stefan

doi:10.1016/j.ijheatfluidflow.2013.05.006

Cited by 13 publications

(2 citation statements)

References 20 publications

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“…Flow over Forward-Facing step (FFS) is one of the important aims for enhancing efficiency of thermal performance. Scheit et al [1] numerically studied turbulent flow over FFS by using direct numerical simulation (DNS) based on finite volume method. Their results showed that there is slightly collected streaklines due to recirculation flow at step.…”

Section: Introductionmentioning

confidence: 99%

Hybrid Al2O3-Cu/water nanofluid flow and heat transfer over vertical double forward-facing step

2021

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Turbulent heat transfer and hybrid Al2O3-Cu/nanofluid over vertical double forward facing-stepis numerically conducted. K-? standard model based on finite volume method in two dimensional are applied to investigate the influences of Reynolds number, step height, volume fractions hybrid Al2O3-Cu/nanofluid on thermal performance. In this paper, different step heights for three cases of vertical double FFS are adopted by five different of volume fractions of hybrid (Al2O3-Cu/water) nanofluid varied for 0.1, 0.33, 0.75, 1, and 2, while the Reynolds number different between 10000 to 40000 with temperature is constant. The main findings revealed that rise in local heat transfer coefficients with raised Reynolds number and maximum heat transfer coefficient was noticed at Re=40000. Also rises in heat transfer coefficient detected with increased volume concentrations of hybrid (Al2O3-Cu/water) nanofluid and the maximum heat transfer coefficient found at hybrid Al2O3-Cu/water nanofluid of 2% in compared with others. It?s also found that rise in surface heat transfer coefficient at 1ststep-case 2 was greater than at 1ststep-case 1 and 3 while was higher at 2ndstep-case 3. Average heat transfer coefficient with Reynolds number for all cases are presented in this paper and found that the maximum average heat transfer coefficient was at case 2 compared with case 1 and 3. Gradually increases in skin friction coefficient remarked at 1stand 2ndsteps of the channel and drop in skin friction coefficient was obtained with increased of Reynolds number. Counter of velocity was presented to show the recirculation regions at first and second steps as clarified the enrichment in heat transfer rate. Furthermore, the counter of turbulence kinetic energy contour was displayed to provide demonstration for achieving thermal performance at second step for all cases.

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Section: Introductionmentioning

confidence: 99%

Hybrid Al2O3-Cu/water nanofluid flow and heat transfer over vertical double forward-facing step

2021

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“…Moreover, the acoustic source seems to be of dipolar nature [12][13][14]. Numerical simulations have also been performed for aeroacoustic analysis of FFS flow configuration [16][17][18][19]. For instance, based on incompressible Large Eddy Simulations (LES) of the FFS flow coupled with Lighthill's analogy formulation to access the far-field acoustic, Ji and Wang [16] showed that the front step acts primarily as a dipole source aligned in the streamwise direction.…”

Section: Introductionmentioning

confidence: 99%

POD and Fourier analyses of a fluid-structure-acoustic interaction problem related to interior car noise

Gaudard

Druault

Marchiano

et al. 2017

Mechanics & Industry

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In order to approach a flow configuration revealing the aerodynamic noise contribution in the interior of road vehicles due to the A-pillar vortex, a numerical simulation of a Forward Facing Step (FFS) coupled with a vibrating structure is performed. This numerical study is based on a weak coupling of three solvers to compute (i) the flow field in interaction with the FFS, (ii) the vibration of the structure and (iii) the acoustic radiation in the open cavity. The purpose of this work is then to evaluate the ability of two different post-processing methods: Proper Orthogonal Decomposition and Fourier Decomposition to identify the origin of the noise radiated into a cavity surrounded by an unsteady flow. Fourier and POD decompositions are then successively performed to extract the part of the aeroacoustic wall pressure field impacting the upper part of an upward step mainly related to the radiated acoustic pressure in the cavity. It is observed that the acoustic part, extracted from the wavenumber frequency decomposition (Fourier analysis) of the wall pressure field generates a non-negligible part of the interior cavity noise. However, this contribution is of several orders smaller than the one related to the aerodynamic part of the pressure field. Moreover, it is shown that the most energetic part of the pressure field (POD analysis) is due to the shear flapping motion and mainly contributes to the low-frequency noise in the cavity. Such post-processing results are of particular interest for future analyzes related to the noise radiated inside a car.

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One-Sided Fluid–Structure–Acoustic Interaction for Turbulent Flow over a Step

Springer

Scheit

Becker

2017

Direct and Large-Eddy Simulation X

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Direct numerical simulation of flow over a forward-facing step – Flow structure and aeroacoustic source regions

Cited by 13 publications

References 20 publications

Hybrid Al2O3-Cu/water nanofluid flow and heat transfer over vertical double forward-facing step

Hybrid Al2O3-Cu/water nanofluid flow and heat transfer over vertical double forward-facing step

POD and Fourier analyses of a fluid-structure-acoustic interaction problem related to interior car noise

One-Sided Fluid–Structure–Acoustic Interaction for Turbulent Flow over a Step

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