An experimental study of viscous vortex rings

1996 ◽  
Vol 21 (5) ◽  
pp. 315-324 ◽  
Author(s):  
M. Dziedzic ◽  
H. J. Leutheusser
Keyword(s):  
Experimental Study ◽  
Vortex Rings

Experimental study of buoyant vortex rings

1983 ◽  
Vol 24 (1) ◽  
pp. 16-21 ◽  
Author(s):  
B. I. Zaslavskii ◽  
I. M. Sotnikov
Keyword(s):  
Experimental Study ◽  
Vortex Rings ◽  
Buoyant Vortex Rings

scholarly journals Experimental study of low inertia vortex rings in shear-thinning fluids

2018 ◽  
Vol 30 (11) ◽  
pp. 113103 ◽  
Author(s):  
O. Bentata ◽  
D. Anne-Archard ◽  
P. Brancher
Keyword(s):  
Experimental Study ◽  
Shear Thinning ◽  
Vortex Rings ◽  
Shear Thinning Fluids

An experimental study of an axisymmetric turbulent pulsed air jet

2009 ◽  
Vol 631 ◽  
pp. 23-63 ◽  
Author(s):  
I. CHOUTAPALLI ◽  
A. KROTHAPALLI ◽  
J. H. ARAKERI
Keyword(s):  
Experimental Study ◽  
Strouhal Number ◽  
Nozzle Exit ◽  
Momentum Flux ◽  
Vortex Rings ◽  
Distinct Region ◽  
Pulsed Jet ◽  
Air Jet ◽  
Random Components ◽  
High Reynolds

An experimental study is carried out to elucidate the structure of a high Reynolds number (~105) turbulent pulsed jet. Particle image velocimetry measurements showed that the near flow field is dominated by a series of vortex rings with jet-like flows in between. The data show that the vortex rings convect at nearly constant speed of 0.6Uj(Uj: mean jet exit velocity) and the spacing between the rings assumes a value of about 0.6/St(St: Strouhal number=fd/Uj, wherefis the pulsing frequency anddis the nozzle exit diameter). With increasing Strouhal number, the rings are closely spaced and the flow tends to assume a steady jet character at five diameters downstream of the nozzle exit. At lower Strouhal numbers there is a distinct region of jet flow in between the rings. Many of the global characteristics, entrainment, mass and momentum flux are essentially determined by the strength and spacing of the rings which, in turn, depend onSt. We show that the increase in momentum is due to both increased momentum flux and overpressure at the exit in accordance with Krueger & Gharib (AIAA J., vol. 43 (4), 2005, p. 792). This increase in momentum comes at the expense of higher energy required to produce the jet. We also present results of organized and random components of the fluctuations and production of the random turbulence in a pulsed jet. The two regions of dominant turbulence production are identified with the ring and the trailing jet shear layers.

Experimental Study of Shock-Generated Vortex Rings

1995 ◽  
pp. 361-366 ◽  
Author(s):  
M. Brouillette ◽  
J. Tardif ◽  
E. Gauthier
Keyword(s):  
Experimental Study ◽  
Vortex Rings

Experimental study on the restoration from a tilt-azimuth series for improvement in resolution

1995 ◽  
Vol 53 ◽  
pp. 636-637
Author(s):  
Norio Baba ◽  
Norihiko Ichise ◽  
Syunya Watanabe
Keyword(s):  
Experimental Study ◽  
Spherical Aberration ◽  
Incident Beam ◽  
Optical Parameters ◽  
Beam Tilting ◽  
Illumination Method ◽  
Restoration Method ◽  
Illumination Mode

The tilted beam illumination method is used to improve the resolution comparing with the axial illumination mode. Using this advantage, a restoration method of several tilted beam images covering the full azimuthal range was proposed by Saxton, and experimentally examined. To make this technique more reliable it seems that some practical problems still remain. In this report the restoration was attempted and the problems were considered. In our study, four problems were pointed out for the experiment of the restoration. (1) Accurate beam tilt adjustment to fit the incident beam to the coma-free axis for the symmetrical beam tilting over the full azimuthal range. (2) Accurate measurements of the optical parameters which are necessary to design the restoration filter. Even if the spherical aberration coefficient Cs is known with accuracy and the axial astigmatism is sufficiently compensated, at least the defocus value must be measured. (3) Accurate alignment of the tilt-azimuth series images.

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