scholarly journals Vortex Streets on a Sphere

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Ghada Alobaidi ◽  
Roland Mallier
Keyword(s):  
Spherical Surface ◽  
Two Dimensional ◽  
Vortex Streets

We consider flows on a spherical surface and use a transformation to transport some well-known periodic two-dimensional vortex streets to that spherical surface to arrive at some new expressions for vortex streets on a sphere.

Wavefronts, light rays and caustic associated with the refraction of a plane wavefront by a conospherical lens

2021 ◽  
Author(s):  
José Israel Galindo-Rodríguez ◽  
Gilberto Silva-Ortigoza
Keyword(s):  
Optical Axis ◽  
Spherical Surface ◽  
Bessel Beam ◽  
Optical Element ◽  
The Other ◽  
Two Dimensional ◽  
Light Rays ◽  
Plane Wavefront ◽  
The Relationship ◽  
Dimensional Surface

Abstract The aim of the present work is to introduce a lens whose faces are a conical surface and a spherical surface. We illuminate this lens by a plane wavefront and its associated refracted wavefronts, light rays and caustic are computed. We find that the caustic region has two branches and can be virtual, real or one part virtual and the other real, depending on the values of the parameters characterizing the lens. Furthermore, we present a particular example where one of the branches of the caustic region is constituted by two segments of a line, one part is real and the other one virtual. The second branch is a two-dimensional surface with a singularity of the cusp ridge type such that its Gaussian curvature is different from zero. It is important to remark that for this example, the two branches of the caustic are disconnected. Because of this property and the result obtained by Berry and Balazs on the relationship between the acceleration of an Airy beam and the curvature of its corresponding caustic, we believe that using this optical element one could generate a scalar optical accelerating beam in the region where the caustic is a two-dimensional surface of revolution, and at the same time a scalar optical beam with similar properties to the Bessel beam of zero order in the region were the real caustic is a segment of a line along the optical axis.

scholarly journals Experiments on quasi-two-dimensional dipolar vortex streets generated by a moving momentum source in a stratified fluid

2011 ◽  
Vol 60 (2) ◽  
pp. 024702
Author(s):  
Zhu Min-Hui ◽  
Wang Xiao-Qing ◽  
Chen Ke ◽  
You Yun-Xiang ◽  
Hu Tian-Qun
Keyword(s):  
Stratified Fluid ◽  
Two Dimensional ◽  
Vortex Streets

Secondary vortex streets in two-dimensional cylinder wakes

1999 ◽  
Vol 25 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Osamu Inoue ◽  
Teruyuki Yamazaki
Keyword(s):  
Secondary Vortex ◽  
Two Dimensional ◽  
Vortex Streets ◽  
Cylinder Wakes

scholarly journals Non-stationary vortex streets in shear flows

2019 ◽  
Vol 55 (6) ◽  
pp. 127-138
Author(s):  
М. V. Кalashnik ◽  
О. G. Chkhetiani
Keyword(s):  
Shear Flows ◽  
Vortex Street ◽  
Two Dimensional ◽  
Free Shear Layer ◽  
Horizontal Shear ◽  
Vortex Streets ◽  
Stationary Vortex ◽  
Spatially Periodic ◽  
Current Lines ◽  
Vorticity Transport

Spatially periodic vortex systems that form due to unstable shear flows are called vortex streets. A number of exact and asymptotic solutions of two-dimensional hydrodynamic equations describing nonstationary vortex streets have been constructed. It is shown that the superposition of the flow with a constant horizontal shear and its perturbations in the form of a nonmodal wave provides an exact solution that describes a nonstationary vortex street with rotating elliptic current lines. The width of the zone occupied by such a vortex street has been determined. The equation of separatrix separating vortex cells with closed current lines from an external meandering flow has been obtained. The influence of the quasi-two-dimensional compressibility and beta effect on the dynamics of vortex streets has been studied based on the potential vorticity transport equation. The solutions describing the formation of vortex streets during the development of an unstable zonal periodic flow and a free shear layer have been constructed using a longwave approximation.

Now & Then: Mapping Out a Career Path: From Sargon to Satellites

1995 ◽  
Vol 1 (7) ◽  
pp. 564-571
Author(s):  
Sue Barnes ◽  
Karen Dee Michalowicz
Keyword(s):  
High School ◽  
Spherical Surface ◽  
Career Path ◽  
Chemical Engineer ◽  
Two Dimensional ◽  
World War ◽  
Map Projection ◽  
Greeting Cards ◽  
Scientists And Engineers ◽  
And Algebra

Now… John Snyder has always loved maps, beginning with his elementary school days in Indianapolis. Everyone who knew John identified him with the maps he loved. Oftentimes the greeting cards he received carried a map motif. When John reached high school, his interest in maps was further developed as he studied trigonometry, calculus, and algebra and could apply the concepts developed in those courses to map projection, the science of transforming the earth's spherical surface to a flat, two-dimensional piece of paper. After high school, John's avid interest in chemistry, coupled with World War II's push for more scientists and engineers, helped him choose a career path as a chemical engineer.

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