Control of Free Turbulent Shear Flows

Fiedler, H. E.

doi:10.1007/3-540-69672-5_6

Cited by 36 publications

(33 citation statements)

References 122 publications

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“…That is, [1] 2b and Q for pulsating jets are always larger than those for a steady jet. Then, the pulsation can enhance mixings.…”

Section: Discussionmentioning

confidence: 96%

“…Various types of forced pulsations or forced perturbations into the mean jet are other potential methods for the mixing/diffusion enhancements (for example, see Fredler (1) and Toyoda (2) ), which are useful not only for industrial applications but also for the jet propulsions of underwater creatures. However, basic characteristics of the pulsating jet have not yet been clear, having some remarkable differences from the well-researched steady jet (for example, see Rajaratnam (3) ) such as larger flow rate and faster velocity decay.…”

Section: Introductionmentioning

confidence: 99%

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An Experimental Study of Amplitude and Frequency Effects upon a Pulsating Jet

Hirata

Kubo

Hatanaka

et al. 2009

JFST

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Pulsating jets are very common and useful in various industrial aspects. However, they have some different basic characteristics from steady jets. In this research, the authors reveal both the frequency and the amplitude effects of pulsations on a jet, including large-amplitude cases. Experiments are conducted at a Reynolds number of 5,000, Strouhal numbers of 0.011 -0.27 and velocity-amplitude ratios of 0.1 -1.0. Using a hot-wire anemometry, the authors show centre velocities, radial profiles, half widths and total flow rates at several positions downward a nozzle exit. From centre velocities and radial profiles, we can see that the streamwise scale of the potential core is less than three times the diameter. From half widths and total flow rates, we can see that the pulsation enhances mixing, and confirm the frequency and the amplitude effects specifically. On the other hand, from centre velocities and radial profiles, we cannot see the both effects clearly. As a result, the authors show the combined frequency-and-amplitude effect upon total flow rate, which consists with small-amplitude results by Crow and Champagne (1971), and find the optimum frequencies.

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“…That is, [1] 2b and Q for pulsating jets are always larger than those for a steady jet. Then, the pulsation can enhance mixings.…”

Section: Discussionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

An Experimental Study of Amplitude and Frequency Effects upon a Pulsating Jet

Hirata

Kubo

Hatanaka

et al. 2009

JFST

View full text Add to dashboard Cite

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“…Conversely, the transverse shear stress u v seems to be altered by the nature of the boundary layers [6]. But it is not possible to accurately analyse these values due to their dependence on several flow parameters [28,40].…”

Section: Reynolds Tensor Analysismentioning

confidence: 94%

“…Indeed, the Reynolds stress profiles (case test 2) are directly conditioned by the use of the Complementary Method. Therefore, with the CM reconstruction method, the resulting velocity field has 20% of the total energy corresponding to the well-known energy contribution of the coherent structures in mixing layer flows [28].…”

Section: Analysis Of Reconstructed Velocity Fieldmentioning

confidence: 99%

“…In fully turbulent flows, the identification and dynamical analysis of coherent structures is particularly difficult due to background fluctuations, phase jittering effects and their random 3D character. Furthermore, the 3D coherent structures characterisation remains complex due to their own definitions and to their dependence on flow parameters [28]. Generally, for coherent structures investigation, an experimental or numerical instantaneous field (velocity, pressure, vorticity or others) is used and can be analysed with instantaneous visualisation techniques or statistical data analysis.…”

Section: Introductionmentioning

confidence: 99%

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Experimental 3D Analysis of the Large Scale Behaviour of a Plane Turbulent Mixing Layer

Druault¹,

Delville²,

Bonnet³

2005

Flow Turbulence Combust

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A new structure education method is proposed for representing the three dimensional large scale structures from hot wires measurement data. Due to the limited number of hot wire probes that can be used simultaneously, we firstly have to optimise the spatial location of sensors in order to detect large scale coherent structures. For such a purpose a detailed analysis of the 3D space-time flow organisation is given with particular emphasis on the full two point correlation tensor of the velocity field. Secondly, several procedures are developed in order to reconstruct instantaneous 3D velocity field on any finer and larger mesh than the experimental one from the limited available experimental information. The particular case of a spatially developing turbulent plane mixing layer is investigated. We then show that Stochastic Estimation and Proper Orthogonal Decomposition lead to a satisfactory reconstruction preserving the 3D coherent character of the flow. Finally, this reconstructed velocity field provides a 3D space-time representation of the large scale structures in a streamwise section of the flow and can then be used as realistic turbulent inflow condition for Large Eddy Simulations.

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Active Control of Kelvin-Helmholtz Waves

Williams

Möhring²

1999

IUTAM Symposium on Mechanics of Passive and Active Flow Control

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Control of Free Turbulent Shear Flows

Cited by 36 publications

References 122 publications

An Experimental Study of Amplitude and Frequency Effects upon a Pulsating Jet

An Experimental Study of Amplitude and Frequency Effects upon a Pulsating Jet

Experimental 3D Analysis of the Large Scale Behaviour of a Plane Turbulent Mixing Layer

Active Control of Kelvin-Helmholtz Waves

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