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
Modeling of dielectric barrier discharge plasma actuator
TL;DR: In this article, the physics of a two-dimensional asymmetric actuator operating in helium gas using a high-fidelity first-principles-based numerical modeling approach was analyzed.
Proceedings ArticleDOI
Numerical Study of Resonant Interactions and Flow Control in a Canonical Separated Flow
TL;DR: In this article, a novel numerical configuration has been devised in order to investigate active control of separated airfoil flows in a comprehensive and systematic manner, which consists of a flat plate at zero degrees angle-of-attack in a freestream on which a separation bubble of prescribed size is created at a prescribed location through blowing and suction on the top boundary of the computational domain.
Journal ArticleDOI
PIV measurements of a zero-net-mass-flux jet in cross flow
Mark Gordon,Julio Soria +1 more
TL;DR: In this paper, phase-averaged in-plane velocity and out-of-plane vorticity vector fields in the jet near field are pre-sented and the time-dependent volume flow is calculated to study the structure of the jets.
Journal ArticleDOI
Numerical simulation of the interaction of a circular synthetic jet with a boundary layer
Jue Zhou,Shan Zhong +1 more
TL;DR: In this article, a 3D numerical simulation of circular synthetic jets issued into a laminar boundary layer developing over a flat plate was undertaken in a complementary manner alongside with an experimental study with the aim of achieving an improved understanding of the fluid mechanics underlying the interaction process between the synthetic jets and the boundary layer.
Journal ArticleDOI
Flow and heat transfer characteristics under synthetic jets impingement driven by piezoelectric actuator
Xiao-ming Tan,Jing-zhou Zhang +1 more
TL;DR: In this article, an experimental measurement utilizing particle image velocimetry (PIV), hotwire anemometer and infrared camera on the synthetic jet impingement cooling driven by piezoelectric actuator was carried out in the present investigation.
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.