Turbulence properties in the cylinder wake at high Reynolds numbers

Braza, Marianna; Perrin, R.; Hoarau, Yannick

doi:10.1016/j.jfluidstructs.2006.04.021

Cited by 126 publications

(91 citation statements)

References 18 publications

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“…Using this mean flow velocity field, the dimensionless recirculation length L/D is then deduced leading to obtain a value of 1.32. This value is quasi-similar to the previous ones (between 1.1 and 1.4) computed from flow field past a circular cylinder at high Reynolds flow (Braza et al, 2006).…”

Section: Reynolds Averaged Field Analysissupporting

confidence: 90%

Time-Resolved PIV investigations of the flow field around cod-end net structures

2011

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a b s t r a c tFlow field measurements past a fixed rigid cod-end structure and past a porous fishing net structure are conducted using Time-Resolved PIV method. The rigid cod-end is first used to characterize finely the wake flow. Proper Orthogonal Decomposition (POD) is then applied in order to extract the large scale energetic vortices of the flow from the measured velocity field. It is then observed that the first POD modes are associated to the Karman's type flow structure of vortex shedding. It is shown that the characteristics of the wake flow behind the rigid cod-end flow configuration compare quite well with previous ones obtained from bluff cylinder or sphere wake analyzes. Second, PIV measurements are performed around a non-rigid bottom trawl which is free to move. Preliminary analyses show that the frequencies associated with the oscillatory motion of the porous structure are the same as the ones detected in the near wake flow demonstrating the lock-in regime. It is then expected that these preliminary results provide some interesting informations about future investigations on the drag force acting on fishing net structure.

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Section: Reynolds Averaged Field Analysissupporting

confidence: 90%

Time-Resolved PIV investigations of the flow field around cod-end net structures

2011

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“…For blu¨-body wake §ows, it is well known that the turbulence intensities are anisotropic [1,13], meaning that for a given location. This was also observed for the current con¦guration [6].…”

Section: Turbulence Levelmentioning

confidence: 99%

“…Even though the instantaneous velocity distributions are inherently nonsymmetric, the time-averaged §ow ¦eld reveals a symmetric pattern dominated by counterrotating vortices forming a recirculation area. In particular, this symmetric layout is observed for (quasi)-two-dimensional (2D) cylinders placed perpendicular to the freestream direction (see, e. g., [1]), since this geometry is ambiguous towards the incidence angle of attack. In contrast, van Oudheusden et al [2] investigate a 2D body with square cross section, revealing distinct changes in the structure of the wake for di¨erent angles of attack in the range of 0 • to 15 • .…”

Section: Introductionmentioning

confidence: 96%

Base-flow sensitivity of a generic rocket forebody towards small freestream angles

Wolf

You

Hörnschemeyer

et al. 2013

Progress in Flight Physics

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Experimental and numerical investigations have been conducted regarding the wake §ow of a generic rocket model in subsonic freestream conditions. The blu¨base geometry evokes a recirculation area represented by counterrotating vortices. Experiments using Particle Image Velocimetry (PIV) demonstrate that the spatial organization of this area is heavily dependent on small freestream angles (α, β < 1 • ), associated with a signi¦cant shift in the base pressure distribution. Numerical studies using Reynolds-Averaged Navier Stokes (RANS) methods with one-and twoequation turbulence models are able to predict the mean velocity ¦eld as well as tendencies regarding α and β, but lack the sensitivity of the experiments. The mean pressure level on the base is calculated within 10% of the experimental value using the two-equation turbulence model, although the pressure distributions on the base show distinct di¨erences. NOMENCLATURE c p,baseBase pressure coef¦cient D Diameter DEHS Di-Ethyl-Hexyl-Sebacat k, TKE Turbulent kinetic energy L Model length Ma ∞

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“…We study the near wake of a square prism because (i) it is numerically less demanding than a DNS of the near field of grid-generated turbulence and is nevertheless a significantly inhomogeneous and anisotropic flow; (ii) power law energy spectra have already been reported in the very near field of planar wakes (Ong & Wallace 1996;Braza et al 2006); and (iii) hot wire anemometry studies of highly reduced forms of the KHMH equation have already been carried out in turbulent planar wakes by Thiesset et al (2011a), Thiesset et al (2011b), Thiesset et al (2013a) and Thiesset et al (2014). This approach can give us the opportunity to both confirm and extend the results of Gomes-Fernandes et al (2015) and Thiesset et al (2013a).…”

Section: Introductionmentioning

confidence: 99%

The turbulence cascade in the near wake of a square prism

2017

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We present a study of the turbulence cascade on the centreline of an inhomogeneous and anisotropic near field turbulent wake generated by a square prism at Re = 3900 using the Kármán-Howarth-Monin-Hill (KHMH) equation. This is the fully generalised scale-by-scale energy balance which, unlike the Kármán-Howarth equation, does not require homogeneity or isotropy assumptions. Our data are obtained from a direct numerical simulation (DNS) and therefore enable us to access all the processes involved in this energy balance. A significant range of length-scales exists where the orientation averaged non-linear interscale transfer rate is approximately constant and negative, indicating a forward turbulence cascade on average. This average cascade consists of coexisting forward and inverse cascade behaviours in different scale space orientations. With increasing distance from the prism but within the near field of the wake, the orientationaveraged non-linear interscale transfer rate tends to be approximately equal to minus the turbulence dissipation rate even though all the inhomogeneity-related energy processes in the scale-by-scale energy balance are significant, if not equally important. We also find well-defined near −5/3 energy spectra in the streamwise direction, in particular at a centreline position where the inverse cascade behaviour occurs for streamwise oriented length-scales.

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Turbulence properties in the cylinder wake at high Reynolds numbers

Cited by 126 publications

References 18 publications

Time-Resolved PIV investigations of the flow field around cod-end net structures

Time-Resolved PIV investigations of the flow field around cod-end net structures

Base-flow sensitivity of a generic rocket forebody towards small freestream angles

The turbulence cascade in the near wake of a square prism

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