Journal ArticleDOI
The formation and evolution of synthetic jets
Barton L. Smith,Ari Glezer +1 more
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In this article, a nominally plane turbulent jet is synthesized by the interactions of a train of counter-rotating vortex pairs that are formed at the edge of an orifice by the time-periodic motion of a flexible diaphragm in a sealed cavity.Abstract:
A nominally plane turbulent jet is synthesized by the interactions of a train of counter-rotating vortex pairs that are formed at the edge of an orifice by the time-periodic motion of a flexible diaphragm in a sealed cavity. Even though the jet is formed without net mass injection, the hydrodynamic impulse of the ejected fluid and thus the momentum of the ensuing jet are nonzero. Successive vortex pairs are not subjected to pairing or other subharmonic interactions. Each vortex of the pair develops a spanwise instability and ultimately undergoes transition to turbulence, slows down, loses its coherence and becomes indistinguishable from the mean jet flow. The trajectories of vortex pairs at a given formation frequency scale with the length of the ejected fluid slug regardless of the magnitude of the formation impulse and, near the jet exit plane, their celerity decreases monotonically with streamwise distance while the local mean velocity of the ensuing jet increases. In the far field, the synthetic jet i...read more
Citations
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Journal ArticleDOI
Effect of driven frequency on flow and heat transfer of an impinging synthetic air jet
TL;DR: In this article, the impingement heat transfer from a synthetic air jet on a heated surface was experimentally studied, and the results showed that the heat transfer enhancement of the synthetic jet was at least double the natural convective heat transfer.
Journal ArticleDOI
Oscillatory flow in jet pumps: Nonlinear effects and minor losses
Andi Petculescu,L. A. Wilen +1 more
TL;DR: A nonresonant, lumped-element technique is used to investigate the behavior of tapered cylindrical flow constrictions (jet pumps) in the nonlinear oscillatory flow regime and the agreement is good, confirming the so-called Iguchi hypothesis.
Journal ArticleDOI
Numerical study and experimental validation of a valveless piezoelectric air blower for fluidic applications
Van Thanh Dau,Thien Xuan Dinh +1 more
TL;DR: In this paper, the authors report the numerical and experimental study of a valveless microblower actuated by a lead zirconate titanate (PZT) diaphragm.
Proceedings ArticleDOI
DNS of micro jets for turbulent boundary layer control
Conrad Y. Lee,David Goldstein +1 more
Journal ArticleDOI
Heat transfer and acoustic study of impinging synthetic jet using diamond and oval shape orifice
TL;DR: In this article, the authors investigated the heat transfer and acoustic properties of impinging synthetic jet with different configurations of diamond and oval shape orifices with same hydraulic diameter at an excitation frequency of 100-250 Hz.
References
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Journal ArticleDOI
An Album of Fluid Motion
Milton van Dyke,Frank M. White +1 more
TL;DR: In this paper, the authors present a visualisation de l'ecoulement for tourbillon and dynamique des: fluides, aubes, cylindre, instabilite.
Journal ArticleDOI
Streamwise vortex structure in plane mixing layers
Luis P. Bernal,Anatol Roshko +1 more
TL;DR: In this paper, it is shown that superimposed on the primary, spanwise vortex structure there is a secondary, steam wise vortex structure, and the spatial organization of the secondary structure produces a well-defined spanwise entrainment pattern in which fluid from each stream is preferentially entrained at different spanwise locations.
Journal ArticleDOI
The planar turbulent jet
Ephraim Gutmark,Israel Wygnanski +1 more
TL;DR: In this article, hot-wire measurements in a plane incompressible jet are reported, where the flow was found to be self-preserving beyond x/d > 40 and measurements were made up to x/D = 120.
Journal ArticleDOI
The structure of a self-preserving turbulent plane jet
TL;DR: The structure of a self-preserving turbulent plane jet exhausting into a slow-moving parallel airstream is studied in this paper, where results of turbulence measurements and the structure is compared with that of the plane wake.
Journal ArticleDOI
Preferred modes and the spreading rates of jets
Ephraim Gutmark,Chih-Ming Ho +1 more
TL;DR: In this article, it is suggested that extremely low-level spatially coherent disturbances in individual facilities change the initial conditions of a laminar shear layer and result in the discrepancies reported in the literature.