Turbulent Hierarchic Structure and Scalar Mixing in a Supersonic Mixing Layer at High Convective Mach Numbers

ASME/JSME 2007 Thermal Engineering Heat Transfer Summer Conference, Volume 1 ◽

10.1115/ht2007-32910 ◽

2007 ◽

Author(s):

Hiroshi Maekawa ◽

Daisuke Watanabe

Keyword(s):

Mach Number ◽

Shear Layer ◽

Turbulent Mixing ◽

Mixing Layer ◽

Structure Evolution ◽

Turbulent Shear ◽

Scalar Mixing ◽

Turbulent Structures ◽

Turbulent Mixing Layer ◽

Hierarchic Structure

Turbulent structures in a supersonic plane mixing layer at the convective Mach number of Mc=1.2 are studied using spatially developing DNS. High-resolution compact upwind-biased schemes developed by Deng & Maekawa (1996)[1] are employed for spatial derivatives. The numerical results indicate that the turbulent structures are generated after transition in the mixing layer, which are similar to the plane jet turbulent shear layer. The mixing layer Reynolds number based on the vorticity thickness reaches 6500. Unlike low Mach number mixing layers with a roller-like structure, hierarchic structures with hairpin packet-like structure and its cluster vortices are observed in the turbulent mixing layer. The effect of the turbulent hierarchic structure on scalar mixing is investigated using the DNS database. The visualized scalar field associated with vortical structure evolution of the turbulent mixing layer shows that the intermittent hairpin packet-like structure and its cluster govern a large-scale scalar mixing in the shear layer. The turbulent fine structure of pair vortices also plays an important role for scalar mixing. Furthermore, dilatational fields of the mixing layer show intense areoacoustic phenomena associated with the turbulent structure evolution.

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The potential flow bounded by a mixing layer and a solid surface

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1984.0101 ◽

1984 ◽

Vol 395 (1809) ◽

pp. 265-290 ◽

Cited By ~ 7

Keyword(s):

Shear Layer ◽

Solid Surface ◽

Turbulent Mixing ◽

Potential Flow ◽

Near Field ◽

Mixing Layer ◽

Detailed Comparison ◽

Mixing Layers ◽

Turbulent Shear ◽

Spatial Correlations

Phillips's ( Proc. Camb. Phil. Soc . 51, 220 (1955)) analysis of the potential 'near field' forced by a turbulent shear layer is extended to include calculation of velocity spectra, spatial correlations and the effect of a solid surface at a finite distance from the shear layer. In the region away from the influence of the wall the theory predicts that correlation scales depend principally on the effective distance from the turbulence. This result suggests that the large correlation scales measured outside turbulent mixing layers do not necessarily demonstrate the essential tow-dimensionality of the large turbulent eddies and shows why mixing layers are more influenced by potential flow effects than are other shear layers. The detailed comparison of the theory to measurements made outside a high Reynolds number single-stream turbulent mixing layer results in an unphysical negative regions are caused by an error in a basic assumption of the theory. However, all the measured correlation scales appear to increase linearly with distance from the turbulence and therefore are consistent with the main result of the analysis. As the potential flow becomes affected by the wind tunnel floor, u 2 — and w 2 — are amplified significantly more than the theory predicts, while v 2 — is not attenuated. These discrepancies are attributed partly to the streamwise inhomogeneity of the flow, which was not incorporated into the analysis.

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C134 Fractal Characteristics o f Scalar Mixing in Chemically Reacting Turbulent Mixing Layer

The Proceedings of the Thermal Engineering Conference ◽

10.1299/jsmeted.2011.71 ◽

2011 ◽

Vol 2011 (0) ◽

pp. 71-72

Author(s):

Kazuki Matsukawa ◽

Naoya Fukushima ◽

Masayasu Shimura ◽

Mamoru Tanahashi ◽

Toshio Miyauchi

Keyword(s):

Turbulent Mixing ◽

Mixing Layer ◽

Scalar Mixing ◽

Turbulent Mixing Layer ◽

Fractal Characteristics ◽

Chemically Reacting

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Mach Number Dependence on Sound Sources in High Mach Number Turbulent Mixing Layer

22nd AIAA/CEAS Aeroacoustics Conference ◽

10.2514/6.2016-3015 ◽

2016 ◽

Cited By ~ 3

Author(s):

Daiki Terakado ◽

Taku Nonomura ◽

Akira Oyama ◽

Kozo Fujii

Keyword(s):

Mach Number ◽

Turbulent Mixing ◽

Mixing Layer ◽

Sound Sources ◽

Turbulent Mixing Layer ◽

High Mach Number ◽

High Mach

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RE-EVALUATING MIXING LENGTH IN TURBULENT MIXING LAYER BY MEANS OF HIGH-ORDER STATISTICS OF VELOCITY FIELD

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194512008690 ◽

2012 ◽

Vol 19 ◽

pp. 154-165 ◽

Cited By ~ 1

Author(s):

KEH-CHIN CHANG ◽

KUAN-HUANG LI ◽

TING-CHENG CHANG

Keyword(s):

Shear Layer ◽

Turbulent Mixing ◽

Near Field ◽

Mixing Layer ◽

Sufficient Conditions ◽

The Self ◽

Linear Growth Rate ◽

Mixing Length ◽

Turbulent Mixing Layer ◽

Low Speed

A turbulent planar mixing layer is composed of two different flow types in its flow field, namely a shear layer in the central region and two free streams in each outer high- and low-speed side. Shear layer is formed after the trailing edge of the splitting plate and develops stream-wisely through successively distinct regions, namely the near field region and the self-preserving region. Two alternative definitions of the mixing lengths (lS and lF) are proposed in terms of the skewness and flatness factors, respectively, which are of third- and fourth-order of turbulence statistics. It is shown that the linear growth rate of the mixing length (either lS or lF) can be, then, used as one of the necessary and sufficient conditions to identify the achievement of the self-preserving state in turbulent mixing layer. Moreover, lF can be taken as the real length scale of the shear layer, which is of shear turbulence, bounded by the two outer high- and low-speed free streams in a given stream-wise station.

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