Experimental study of the production of vortex rings using a variable diameter orifice

2005 ◽  
Vol 17 (6) ◽  
pp. 061701 ◽  
Author(s):  
J. J. Allen ◽  
T. Naitoh
Keyword(s):  
Experimental Study ◽  
Vortex Rings ◽  
Variable Diameter ◽  
Diameter Orifice

scholarly journals Experimental evaluation of the light sword lens performance with a variable pupil size

2018 ◽  
Vol 10 (2) ◽  
pp. 36 ◽  
Author(s):  
Walter Torres-Sepúlveda ◽  
Alejandro Mira-Agudelo ◽  
John Fredy Barrera ◽  
Andrzej Kolodziejczyk
Keyword(s):  
New York ◽  
Experimental Study ◽  
Pupil Size ◽  
Focal Depth ◽  
Optical Element ◽  
Depth Of Focus ◽  
Variable Diameter ◽  
Diffraction Structure ◽  
Do So

This paper presents an experimental study designed to test the performance of the light sword lens (LSL) with different pupil sizes. To do so, Snellen optotype images obtained by a monofocal lens either with or without an LSL, were compared. Images were obtained for three different pupil sizes at several target vergences. The correlation coefficient and through-focus curves were obtained and compared. The experimental results show differences in the contrast and the depth of focus with different pupil sizes using the monofocal lens without an LSL. In contrast, when using the monofocal lens in combination with the LSL, the quality of the images is similar for all pupils and target vergences used, with slight differences only in halos and contrast. Full Text: PDF ReferencesG. Mikula, Z. Jaroszewicz, A. Kolodziejczyk, K. Petelczyc, M. Sypek, G. P. Agrawal, "Imaging with extended focal depth by means of lenses with radial and angular modulation", Opt Express 15, 9184, (2007). CrossRef A. Kolodziejczyk, S. Bará, Z. Jaroszewicz, M. Sypek, "The Light Sword Optical Element—a New Diffraction Structure with Extended Depth of Focus", J. Mod Opt. 37, 1283, (1990). CrossRef K. Petelczyc et al, "Presbyopia compensation with a light sword optical element of a variable diameter", Photonics Lett. Pol. 1, 55 (2009). DirectLink A. Mira-Agudelo et al, "Compensation of Presbyopia With the Light Sword Lens", Invest Ophthalmol Vis Sci 57, 6871, (2016). CrossRef R.A. Fisher, Statistical Methods for Research Workers (New York, Hafner, 13th Ed., 1958) CrossRef

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

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

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
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