scholarly journals Coherent Structures of the Turbulent Mixing Layer at High Reynolds Numbers. 1st Report. Instantaneous Structures and Phase-Averaged Flow Features of the Large-Scale Motion.

1995 ◽  
Vol 61 (588) ◽  
pp. 2841-2848
Author(s):  
Hironori Takahashi ◽  
Hiroshi Maekawa ◽  
Joel Delville ◽  
Jean-Paul Bonnet
Keyword(s):  
Coherent Structures ◽  
Turbulent Mixing ◽  
Large Scale ◽  
Mixing Layer ◽  
Reynolds Numbers ◽  
Turbulent Mixing Layer ◽  
High Reynolds Numbers ◽  
Flow Features ◽  
High Reynolds ◽  
Scale Motion

Coherent structures in coflowing jets and wakes

1978 ◽  
Vol 88 (3) ◽  
pp. 451-463 ◽  
Author(s):  
A. E. Perry ◽  
T. T. Lim
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Glass Tube ◽  
Reynolds Numbers ◽  
Reynolds Number Flow ◽  
Naturally Occurring ◽  
Number Flow ◽  
High Reynolds ◽  
Scale Motion

By applying small lateral oscillations to a glass tube from which smoke was issuing, perfectly periodic coflowing jets and wake structures were produced at Reynolds numbers of order 300-1000. These structures remained coherent over long streamwise distances and appeared to be perfectly frozen when viewed under stroboscopic light which was synchronized with the disturbing oscillation. By the use of strobing laser beams, longitudinal sections of the structures were photographed and an account of the geometry of these structures is reported.When the tube was unforced, similar structures occurred but they modulated in scale and frequency, and their orientation was random.A classification of structures is presented and examples are demonstrated in naturally occurring situations such as smoke from a cigarette, the wake behind a three-dimensional blunt body, and the high Reynolds number flow in a plume from a chimney. It is suggested that an examination of these structures may give some insight into the large-scale motion in fully turbulent flow.

Reconstruction of large coherent structures from SPIV measurements in a forced turbulent mixing layer

2005 ◽  
Vol 39 (4) ◽  
pp. 761-770 ◽  
Author(s):  
E. Kit ◽  
O. Krivonosova ◽  
D. Zhilenko ◽  
D. Friedman
Keyword(s):  
Coherent Structures ◽  
Turbulent Mixing ◽  
Mixing Layer ◽  
Turbulent Mixing Layer

Saturation of inertial instability in rotating planar shear flows

2007 ◽  
Vol 583 ◽  
pp. 413-422 ◽  
Author(s):  
R. C. KLOOSTERZIEL ◽  
P. ORLANDI ◽  
G. F. CARNEVALE
Keyword(s):  
Mixing Layer ◽  
Reynolds Numbers ◽  
Total Momentum ◽  
Simple Construction ◽  
Barotropic Instability ◽  
High Reynolds Numbers ◽  
Planar Shear ◽  
Inertial Instability ◽  
High Reynolds ◽  
Stream Direction

Inertial instability in a rotating shear flow redistributes absolute linear momentum in such a way as to neutralize the instability. In the absence of other instabilities, the final equilibrium can be predicted by a simple construction based on conservation of total momentum. Numerical simulations, invariant in the along-stream direction, suppress barotropic instability and allow only inertial instability to develop. Such simulations, at high Reynolds numbers, are used to test the theoretical prediction. Four representative examples are given: a jet, a wall-bounded jet, a mixing layer and a wall-bounded shear layer.

Large-scale structures in a forced turbulent mixing layer

1985 ◽  
Vol 150 ◽  
pp. 23-39 ◽  
Author(s):  
M. Gaster ◽  
E. Kit ◽  
I. Wygnanski
Keyword(s):  
Turbulent Mixing ◽  
Large Scale ◽  
Phase Distribution ◽  
Mixing Layer ◽  
Global Scale ◽  
Travelling Wave ◽  
Mean Flow ◽  
Turbulent Mixing Layer ◽  
Large Scale Structures ◽  
Scale Structures

The large-scale structures that occur in a forced turbulent mixing layer at moderately high Reynolds numbers have been modelled by linear inviscid stability theory incorporating first-order corrections for slow spatial variations of the mean flow. The perturbation stream function for a spatially growing time-periodic travelling wave has been numerically evaluated for the measured linearly diverging mean flow. In an accompanying experiment periodic oscillations were imposed on the turbulent mixing layer by the motion of a small flap at the trailing edge of the splitter plate that separated the two uniform streams of different velocity. The results of the numerical computations are compared with experimental measurements.When the comparison between experimental data and the computational model was made on a purely local basis, agreement in both the amplitude and phase distribution across the mixing layer was excellent. Comparisons on a global scale revealed, not unexpectedly, less good accuracy in predicting the overall amplification.

How Turbulence Models Perform in Simulating Pipeflow Response to Targeted Wall-Shapes?

2021 ◽  
Author(s):  
Mehran Masoumifar ◽  
Suyash Verma ◽  
Arman Hemmati
Keyword(s):  
Three Dimensional ◽  
Turbulence Models ◽  
Reynolds Numbers ◽  
Navier Stokes ◽  
Flow Response ◽  
High Reynolds Numbers ◽  
Flow Features ◽  
Rans Models ◽  
Response And Recovery ◽  
High Reynolds

Abstract This study evaluates how Reynolds-Averaged-Navier-Stokes (RANS) models perform in simulating the characteristics of mean three-dimensional perturbed flows in pipes with targeted wall-shapes. Capturing such flow features using turbulence models is still challenging at high Reynolds numbers. The principal objective of this investigation is to evaluate which of the well-established RANS models can best predict the flow response and recovery characteristics in perturbed pipes at moderate and high Reynolds numbers (10000-158000). First, the flow profiles at various axial locations are compared between simulations and experiments. This is followed by assessing the well-known mean pipeflow scaling relations. The good agreement between our computationally predicted data using Standard k-epsilon model and those of experiments indicated that this model can accurately capture the pipeflow characteristics in response to introduced perturbation with smooth sinusoidal axial variations.

Large-scale clustering of coherent fine-scale eddies in a turbulent mixing layer

2018 ◽  
Vol 72 ◽  
pp. 100-108
Author(s):  
Toshitaka Itoh ◽  
Yoshitsugu Naka ◽  
Yuki Minamoto ◽  
Masayasu Shimura ◽  
Mamoru Tanahashi
Keyword(s):  
Turbulent Mixing ◽  
Large Scale ◽  
Mixing Layer ◽  
Fine Scale ◽  
Turbulent Mixing Layer
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