Journal ArticleDOI
Acoustic streaming in swirling flow and the Ranque—Hilsch (vortex-tube) effect
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In this paper, the authors demonstrate that the acoustic streaming induced by the pure tone, a spinning wave corresponding to the first tangential mode, deforms the base Rankine vortex into a forced vortex, resulting in total temperature separation in the radial direction.Abstract:
The Ranque–Hilsch effect, observed in swirling flow within a single tube, is a spontaneous separation of total temperature, with the colder stream near the tube centreline and the hotter air near its periphery. Despite its simplicity, the mechanism of the Ranque–Hilsch effect has been a matter of long-standing dispute. Here we demonstrate, through analysis and experiment, that the acoustic streaming, induced by orderly disturbances within the swirling flow is, to a substantial degree, a cause of the Ranque–Hilsch effect. The analysis predicts that the streaming induced by the pure tone, a spinning wave corresponding to the first tangential mode, deforms the base Rankine vortex into a forced vortex, resulting in total temperature separation in the radial direction. This is confirmed by experiments, where, in the Ranque–Hilsch tube of uniflow arrangement, we install acoustic suppressors of organ-pipe type, tuned to the discrete frequency of the first tangential mode, attenuate its amplitude, and show that this does indeed reduce the total temperature separation.read more
Citations
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Microscale acoustofluidics: Microfluidics driven via acoustics and ultrasonics
James Friend,Leslie Y. Yeo +1 more
TL;DR: In this article, the use of acoustic fields, principally ultrasonics, for application in microfluidics is reviewed, and the abundance of interesting phenomena arising from nonlinear interactions in ultrasound that easily appear at these small scales is considered, especially in surface acoustic wave devices that are simple to fabricate with planar lithography techniques.
Journal ArticleDOI
Vortex breakdown: a review
O. Lucca-Negro,Timothy O'Doherty +1 more
TL;DR: The authors reviewed the studies undertaken on vortex breakdown over the past 45 years and provided a "guide" to the literature and where necessary directed the reader to more indepth reviews in specific areas.
Journal ArticleDOI
Recent advances in aero-optics
TL;DR: A brief discussion of the traditional approach to quantifying aero-optic interactions is given in this paper, where the authors review how the development of high-speed wavefront sensors over the past 10 years has impacted the fluid-dynamics and optics fields.
Journal ArticleDOI
Parametric and internal study of the vortex tube using a CFD model
TL;DR: In this paper, a two-dimensional axi-symmetric CFD model has been developed to investigate the energy separation mechanism and flow phenomena within a counter-flow vortex tube.
Journal ArticleDOI
Review of Ranque–Hilsch effects in vortex tubes
TL;DR: In this article, the authors present an overview of the phenomena occurring inside the vortex tube during the temperature/energy separation on both the counter flow and parallel flow types, and present several different hypotheses based on experimental, analytical, and numerical studies.
References
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On density effects and large structure in turbulent mixing layers
Garry L. Brown,Anatol Roshko +1 more
TL;DR: In this article, Spark shadow pictures and measurements of density fluctuations suggest that turbulent mixing and entrainment is a process of entanglement on the scale of the large structures; some statistical properties of the latter are used to obtain an estimate of entrainedment rates, and large changes of the density ratio across the mixing layer were found to have a relatively small effect on the spreading angle.
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On a Peculiar Class of Acoustical Figures; and on Certain Forms Assumed by Groups of Particles upon Vibrating Elastic Surfaces
TL;DR: Chladni as mentioned in this paper observed that shavings from the hairs of the exciting violin bow did not proceed to the nodal lines, but were gathered together on those parts of the plate the most violently agitated, i. e. at the centres of oscillation.
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The use of the expansion of gases in a centrifugal field as cooling process.
TL;DR: The design of a vortex tube of good efficiency in which the expansion of a gas in a centrifugal field produces cold is described and the important variables in construction and operation are discussed and data for several tubes under various operating conditions are given.