Aerodynamic Flow-Vectoring of a Planar Jet in a Co-Flowing Stream

2004 ◽  
Author(s):  
Diego Arcas ◽  
Panom Intarussamee ◽  
Larry Redekopp
Keyword(s):  
Planar Jet ◽  
Flowing Stream

Aerodynamic flow-vectoring of a planar jet in a co-flowing stream

2002 ◽  
Vol 450 ◽  
pp. 343-375 ◽  
Author(s):  
DAVID W. LIM ◽  
LARRY G. REDEKOPP
Keyword(s):  
Flow Control ◽  
Velocity Ratio ◽  
Shear Layers ◽  
Control Input ◽  
Local Flow ◽  
Control Approach ◽  
Planar Jet ◽  
Symmetric Configuration ◽  
Thrust Vector ◽  
Flowing Stream

The vectoring of an incompressible, two-dimensional jet in a co-flowing stream is investigated by means of direct numerical simulation. The control input used to stimulate jet vectoring is accomplished through distributed suction from blunt-faced lips at the exit of the jet. The thrust vector methodology is based on suppression of global instabilities in the wake-shear layers formed between the co-flow and the jet. Once a critical suction volume flux needed to suppress these global instabilities is exceeded, local flow control can be realized through varying the distribution of suction across the base of the jet lips. It is found that the critical suction flux scales primarily with the ambient co-flow, not with the jet speed, and that lift-to-thrust ratios exceeding 15% can be realized. The effects of jet Reynolds number, jet-to- ambient velocity ratio, boundary-layer thickness, and geometric parameters on various performance characteristics are examined. It is also shown that the asymmetric flow control approach used for vectoring the jet can also be implemented in a symmetric configuration to enhance jet spreading. Significant increases in jet spreading can be realized when the symmetrically applied suction flux is sufficient to stimulate the sinuous mode of instability of the jet such that energetic apping motion ensues.

Characteristics of small-scale shear layers in a temporally evolving turbulent planar jet

2021 ◽  
Vol 920 ◽  
Author(s):  
Masato Hayashi ◽  
Tomoaki Watanabe ◽  
Koji Nagata
Keyword(s):  
Shear Layers ◽  
Small Scale ◽  
Planar Jet ◽  
Scale Shear

Abstract

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):  
Planar Jet

Effects of Pressure on Spray Evaporation in a Planar Jet

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

scholarly journals High concentration Brownian coagulation in jet flow using two enhancement formulations

2012 ◽  
Vol 16 (5) ◽  
pp. 1519-1523
Author(s):  
Pei-Feng Lin ◽  
Di-Chong Wu ◽  
Ze-Fei Zhu
Keyword(s):  
Volume Fraction ◽  
Taylor Series Expansion ◽  
Expansion Method ◽  
High Volume ◽  
Jet Flow ◽  
High Concentration ◽  
Brownian Coagulation ◽  
Planar Jet ◽  
Ultra Fine Particle ◽  
The One

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.

Evolution and Turbulence Properties of Self-Sustained Transversely Oscillating Flow Induced by Fluidic Oscillator

2007 ◽  
Vol 129 (8) ◽  
pp. 1038-1047 ◽  
Author(s):  
Rong Fung Huang ◽  
Kuo Tong Chang
Keyword(s):  
Stagnation Point ◽  
Vortex Pair ◽  
Transverse Oscillation ◽  
Oscillating Flow ◽  
Near Wake ◽  
Fluidic Oscillator ◽  
Planar Jet ◽  
Oscillation Process ◽  
Gravity Driven ◽  
Flow Evolution

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.

External Excitation of Planar Jets

1972 ◽  
Vol 39 (4) ◽  
pp. 883-890 ◽  
Author(s):  
D. O. Rockwell
Keyword(s):  
Reynolds Number ◽  
Vortex Formation ◽  
External Excitation ◽  
Formation Region ◽  
Initial Formation ◽  
Planar Jet ◽  
Periodic Disturbances ◽  
Wide Range

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.

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