Streamwise evolution of a high-Schmidt-number passive scalar in a turbulent plane wake

2001 ◽  
Vol 31 (2) ◽  
pp. 186-192 ◽  
Author(s):  
H. Rehab ◽  
R. A. Antonia ◽  
L. Djenidi
Keyword(s):  
Schmidt Number ◽  
Passive Scalar ◽  
High Schmidt Number ◽  
Plane Wake ◽  
Turbulent Plane

scholarly journals Spectrum of Passive Scalar at Very High Schmidt Number in Turbulence

2015 ◽  
Vol 9 (0) ◽  
pp. 3401019-3401019 ◽  
Author(s):  
Toshiyuki GOTOH ◽  
Takeshi WATANABE ◽  
Hideaki MIURA
Keyword(s):  
Schmidt Number ◽  
Passive Scalar ◽  
High Schmidt Number ◽  
Very High

Comparison of Subgrid Closure Methods for Passive Scalar Variance at High Schmidt Number

2015 ◽  
Vol 38 (11) ◽  
pp. 2087-2095 ◽  
Author(s):  
Krzysztof Wojtas ◽  
Łukasz Makowski ◽  
Wojciech Orciuch ◽  
Jerzy Bałdyga
Keyword(s):  
Schmidt Number ◽  
Passive Scalar ◽  
High Schmidt Number ◽  
Scalar Variance

Derivative Statistics of Axial Velocity and Passive Scalar in the Jet Diffusion Field of High-Schmidt-Number Matter

2007 ◽  
Author(s):  
Y. Sakai ◽  
K. Uchida ◽  
T. Kubo ◽  
K. Nagata
Keyword(s):  
Axial Velocity ◽  
Schmidt Number ◽  
Water Solution ◽  
Passive Scalar ◽  
Streamwise Velocity ◽  
The Other ◽  
Diffusion Field ◽  
High Schmidt Number ◽  
Velocity Derivative ◽  
Flatness Factor

In this study, a water solution of dye (whose Schmidt number is about 3,800) was issued into the quiescent water as an axisymmetric turbulent jet and the simultaneous measurements of axial velocity and concentration have been performed using the combined probe of I-type hot-film and fiber-optic concentration sensor based on the Lambert-Beer’s law. Then we calculated the PDF (Probability Density Function) for the streamwise velocity derivative ∂u/∂x and streamwise concentration derivative ∂c/∂x. It was confirmed that the PDFs for ∂u/∂x skew negatively, and the values of skewness (S∂u/∂x) and flatness factor (F∂u/∂x) are consistent with the other data (see Sreenivasan and Antonia, 1997). However, with regard to the PDFs for ∂c/∂x, the skewness (S∂c/∂x) show the values very close to zero, unlikely the past other data which show the magnitude of 0.5∼1.0. On the other hand, the flatness factor (F∂c/∂x) show the values of 7.0∼8.0 which are consistent with other data. This result suggests that the fine-scale structure of a high-Schmidt-number diffusion field is almost isotropic although it is intermittent.

The geometric properties of high-Schmidt-number passive scalar iso-surfaces in turbulent boundary layers

2007 ◽  
Vol 588 ◽  
pp. 253-277 ◽  
Author(s):  
L. P. DASI ◽  
F. SCHUERG ◽  
D. R. WEBSTER
Keyword(s):  
Scalar Field ◽  
Boundary Layers ◽  
Schmidt Number ◽  
Passive Scalar ◽  
Turbulent Boundary Layers ◽  
Length Scale ◽  
Geometric Properties ◽  
Convective Regime ◽  
High Schmidt Number ◽  
Kolmogorov Scale

The geometric properties are quantified for concentration iso-surfaces of a high-Schmidt-number passive scalar field produced by an iso-kinetic source with an initial finite characteristic length scale released into the inertial layer of fully developed open-channel-flow turbulent boundary layers. The coverage dimension and other measures of two-dimensional transects of the passive scalar iso-surfaces are found to be scale dependent. The coverage dimension is around 1.0 at the order of the Batchelor length scale and based on our data increases in a universal manner to reach a local maximum at a length scale around the Kolmogorov scale. We introduce a new parameter called the coverage length underestimate, which demonstrates universal behaviour in the viscous–convective regime for these data and hence is a potentially useful practical tool for many mixing applications. At larger scales (in the inertial–convective regime), the fractal geometry measures are dependent on the Reynolds number, injection length scale, and concentration threshold of the iso-surfaces. Finally, the lacunarity of the iso-surface structure shows that the instantaneous scalar field is most inhomogenous around the length scale corresponding to the Kolmogorov scale.

An Experimental Study on Turbulent Mixing of High-Schmidt-Number Scalar in Grid Turbulence by Means of PIV and PLIF

2011 ◽  
Author(s):  
Hiroki Suzuki ◽  
Kouji Nagata ◽  
Yasuhiko Sakai ◽  
Ryota Ukai
Keyword(s):  
Turbulent Mixing ◽  
Schmidt Number ◽  
Water Channel ◽  
Concentration Field ◽  
Outer Region ◽  
Passive Scalar ◽  
Spatiotemporal Variation ◽  
Grid Turbulence ◽  
High Schmidt Number ◽  
Scalar Variance

Turbulent mixing of high-Schmidt-number passive scalar in shear-free grid turbulence is experimentally investigated using a water channel. The Reynolds number based on the mesh size of the grid and cross-sectionally averaged mean velocity is 2,500. Rhodamine B (fluorescent dye) was used as a high-Schmidt-number passive scalar. The Schmidt number is about 2,100. The time-resolved particle image velocimetry (PIV) and the planar laser induced fluorescence (PLIF) technique were used to measure instantaneous two-component velocities and nondimensional concentration. Our PLIF algorithm corrects the following errors: spatiotemporal variation of local excitation intensity due to an inhomogeneous concentration field along the light path, time variation of fluorescence quantum yield, and spatiotemporal variation of incident laser intensity. The results show that the vertical profile of mean scalar can be well approximated by the error function. In contrast, the profile of scalar variance in outer region of the mixing layer cannot be approximated by the Gaussian profile. In addition, the half width of mean scalar is larger than that of the scalar variance profile.

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