The relation between shearing motions and the turbulent/non-turbulent interface in a turbulent planar jet

2021 ◽  
Vol 33 (5) ◽  
pp. 055126
Author(s):  
M. Hayashi ◽  
T. Watanabe ◽  
K. Nagata
Keyword(s):  
2021 ◽  
Vol 920 ◽  
Author(s):  
Masato Hayashi ◽  
Tomoaki Watanabe ◽  
Koji Nagata

Abstract


2009 ◽  
Author(s):  
Mariko Nakamura ◽  
Theodore E. Simos ◽  
George Psihoyios ◽  
Ch. Tsitouras
Keyword(s):  

2012 ◽  
Vol 16 (5) ◽  
pp. 1519-1523
Author(s):  
Pei-Feng Lin ◽  
Di-Chong Wu ◽  
Ze-Fei Zhu

Ultra-fine particle coagulation by Brownian motion at high concentration in planar jet flow is simulated. A Taylor-Series Expansion Method of Moments is employed to solve the particle general dynamic equation. The volume fraction gets high value, very closes to that at the nozzle exit. As the vortex pairing develops, the high volume fraction region rolls out and mixes with the low value region. The enhancement factor given by Trzeciak et al. will be less than one at some specific outer positions, which seems to be less accurate than the one given by Heine et al.


2007 ◽  
Vol 129 (8) ◽  
pp. 1038-1047 ◽  
Author(s):  
Rong Fung Huang ◽  
Kuo Tong Chang

The evolution process and turbulence properties of a transversely oscillating flow induced by a fluidic oscillator are studied in a gravity-driven water tunnel. A planar jet is guided to impinge a specially designed crescent surface of a target blockage that is enclosed in a cavity of a fluidic oscillator. The geometric configuration of the cavity transforms the inherent stability characteristics of the jet from convective instability to absolute instability, so that the jet precedes the persistent back and forth swinging in the cavity. The swinging jet is subsequently directed through two passages and issued alternatively out of the fluidic oscillator. Two short plates are installed near the exits of the alternatively issuing pulsatile jets to deflect the jets toward the central axis. The deflected jets impinge with each other and form a pair of counter-rotating vortices in the near wake of the oscillator with a stagnation point at the impingement point. The stagnation point of the counter-rotating vortex pair moves back and forth transversely because of the phase difference existing between the two issued jets. The merged flow evolving from the counter-rotating vortices formed by the impingement of the two pulsatile jets therefore presents complex behavior of transverse oscillation. The topological models corresponding to the flow evolution are constructed to illustrate the oscillation process of the oscillating flow. Significant momentum dispersion and large turbulence intensity are induced by the transverse oscillation of the merged flow. The statistical turbulence properties show that the Lagrangian integral time and length scales of the turbulence eddies (the fine-scale structure) produced in the oscillating flow are drastically reduced.


1972 ◽  
Vol 39 (4) ◽  
pp. 883-890 ◽  
Author(s):  
D. O. Rockwell

A planar jet was subjected to transverse periodic disturbances of appropriate dimension-less frequency such that the vortex growth of the jet could be controlled for a wide range of jet Reynolds number (1860 to 10,800). Changes in the apparent time mean characteristics of the jet in its initial formation region, due to the applied disturbances, are related to the behavior of vortices. The processes of vortex formation, growth, and coalescence in the initial formation region are portrayed. The alterations of these processes as a function of the dimensionless applied disturbance are classed into regimes identified with respect to the natural breakdown state of the jet.


1986 ◽  
Vol 163 ◽  
pp. 227-256 ◽  
Author(s):  
F. O. Thomas ◽  
V. W. Goldschmidt

An experimental study of the developing structural characteristics of a two-dimensional jet in an extremely quiet environment was performed. The jet, at an exit Reynolds number of 6000 and with fluctuation intensity under 0.2% at the mouth, was operated within a large anechoic room. Measurements of energy spectra, fluctuation phase angles and two-dimensionality led to the inference of structural patterns in the flow. These patterns are initially characterized by relatively strong symmetric modes exhibiting limited two-dimensionality and oriented parallel to the mouth of the jet. Subsequent downstream evolution led to the formation of an antisymmetric pattern beyond the jet potential core and the associated development of extended structures possessing a definite large lateral inclination. The results of this work suggest a developing large-scale structural pattern more complicated than previously supposed.


AIAA Journal ◽  
1994 ◽  
Vol 32 (2) ◽  
pp. 317-323 ◽  
Author(s):  
Robert B. Farrington ◽  
Scott D. Claunch

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