Journal ArticleDOI
Vortex induction and mass entrainment in a small-aspect-ratio elliptic jet
Chih-Ming Ho,Ephraim Gutmark +1 more
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TLDR
In this article, a passive technique of increasing entrainment was found by using a small-aspect-ratio elliptic jet, which was several times greater than that of a circular jet or a plane jet.Abstract:
A passive technique of increasing entrainment was found by using a small-aspect-ratio elliptic jet. The entrainment ratio of an elliptic jet was several times greater than that of a circular jet or a plane jet. The self-induction of the asymmetric coherent structure caused azimuthal distortions which were responsible for engulfing large amounts of surrounding fluid into the jet. In an elliptic jet, an interesting feature in the initial stability process is that the thickness of the shear layer varies around the nozzle. The data indicated that instability frequency was scaled with the thinnest initial momentum thickness which was associated with the maximum vorticity. Turbulence properties were also examined and were found to be significantly different in the major- and minor-axis planes.read more
Citations
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Book ChapterDOI
Particle Image Velocimetry
TL;DR: In this paper, the authors use hot-wire (HW) or laser velocimetry (LV) to estimate the velocity, vorticity, and pressure fields of wake flows.
BookDOI
The MEMS Handbook
TL;DR: In this paper, the authors present a detailed overview of the history of the field of flow simulation for MEMS and discuss the current state-of-the-art in this field.
Journal ArticleDOI
Flow control with noncircular jets
TL;DR: Noncircular jets have been identified as an efficient technique of passive flow control that allows significant improvements of performance in various practical systems at a relatively low cost because noncircular jet rely solely on changes in the geometry of the nozzle as discussed by the authors.
Journal ArticleDOI
Elliptic jets. I - Characteristics of unexcited and excited jets
Fazle Hussain,Hyder S. Husain +1 more
TL;DR: Experimental studies of incompressible elliptic jets of different aspect ratios and initial conditions are summarized along with the effects of excitations at selected frequencies and amplitudes in this paper, where the experimental facilities and procedures are described and jet spread and decay are discussed.
Journal ArticleDOI
Control of an axisymmetric jet using vortex generators
TL;DR: In this article, the effect of vortex generators at the nozzle exit on the evolution of a jet was investigated, and the results of an experimental investigation on the effect on the vortex generators were reported.
References
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Journal ArticleDOI
Orderly Structure in Jet Turbulence
S. C. Crow,F. H. Champagne +1 more
TL;DR: In this paper, the authors show that a large-scale orderly pattern may exist in the noiseproducing region of a round subsonic jet by observing the evolution of orderly flow with advancing Reynolds number.
Journal ArticleDOI
Vortex pairing : the mechanism of turbulent mixing-layer growth at moderate Reynolds number
C. D. Winant,F. K. Browand +1 more
TL;DR: A mixing layer is formed by bringing two streams of water, moving at different velocities, together in a lucite-walled channel as mentioned in this paper, where dye is injected between the two streams just before they are brought together, marking the vorticitycarrying fluid.
Journal ArticleDOI
Some measurements in the self preserving jet
Israel Wygnanski,H. E. Fiedler +1 more
TL;DR: In this paper, the axisymmetric turbulent incompressible and isothermal jet was investigated by use of linearized constant-temperature hot-wire anemometers and the quantities measured include mean velocity, turbulence stresses, intermittency, skewness and flatness factors, correlations, scales, low-frequency spectra and convection velocity.
Journal ArticleDOI
On spatially growing disturbances in an inviscid shear layer
TL;DR: In this paper, the authors used the hyperbolic-tangent velocity profile of the disturbed shear layer to obtain better agreement with experimental results by means of the inviscid linearized stability theory of spatially growing disturbances.
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Elliptic jets. I - Characteristics of unexcited and excited jets
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