ZIB

1

Digitale Medien

Model Experiments for Vortex Columns in the Atmosphere (1963)

MORTON, B. R.

[s.l.] : Nature Publishing Group

Nature 197 (1963), S. 840-842

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1476-4687

Quelle: Nature Archives 1869 - 2009

Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik

Notizen: [Auszug] ORGANIZED colums of vorticity are observed in many parts of the Earth's atmosphere, in such forms as dust whirls and dust devils, tornadoes, waterspouts, fire storms and hurricanes. These columnar flows cover a very wide range of horizontal lenght and velocity scales, say, 10 m-2000 km in lengh and ...

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1038/197840a0

Permalink

Bibliothek	Standort	Signatur	Band/Heft/Jahr	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

2

Digitale Medien

The streaming flow initiated by oscillating cascades of cylinders and their stability (1994)

Yan, B. ; Ingham, D. B. ; Morton, B. R.

[S.l.] : American Institute of Physics (AIP)

Physics of Fluids 6 (1994), S. 1472-1481

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1089-7666

Quelle: AIP Digital Archive

Thema: Physik

Notizen: The steady fluid flow that is initiated by a cascade of cylinders, which oscillates harmonically in an unbounded, incompressible, viscous fluid that is otherwise at rest, is investigated, both numerically and experimentally. Finite-difference techniques are used to obtain the numerical solutions, and the streaming flow results show a reasonable agreement with the experimental data. It is found, both numerically and experimentally, that for large values of the streaming Reynolds number, Rs, the flow is not symmetrical about the axis of the oscillation, i.e., there exists a critical value of Rs, Rs0 say, such that the streaming flows for Rs(approximately-greater-than)Rs0 are unstable and those for Rs〈Rs0 are stable. In order to understand this asymmetry, a stability analysis is performed, and the agreement between the theory and the experimental results is encouraging.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.868262

Permalink

Bibliothek	Standort	Signatur	Band/Heft/Jahr	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

3

Digitale Medien

Drop-formed vortex rings—The generation of vorticity (1995)

Cresswell, R. W. ; Morton, B. R.

[S.l.] : American Institute of Physics (AIP)

Physics of Fluids 7 (1995), S. 1363-1370

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1089-7666

Quelle: AIP Digital Archive

Thema: Physik

Notizen: Vortex rings are seen to form when dyed water drops strike a water surface and their formation and structure depend on height of fall and surface tension. The assumption that a vortex sheet envelopes the penetrating drop, frequently stated without explanation in the literature, does not explain these factors and this paper shows why it is incorrect. Alternative mechanisms have been proposed in the literature but none explains adequately the vorticity generation or the restriction of vortex ring formation to low Weber numbers. This paper proposes a mechanism based on the generation of vorticity on relaxation of surface stresses at coalescence. The condition that the surface viscous stress be continuous across the water-air interface leads to a boundary condition on vorticity and the total amount of vorticity generated depends on the quantity which can be diffused into the fluid interior from the boundary during coalescence. At low values of Weber number this condition appears to be sufficient to generate enough vorticity to allow flow separation at the surface, such separation being a necessary condition for vortex sheet roll-up and ring production. The existence of a critical Weber number above which vortex rings do not form is the result of a balance between the rate at which the ring of contact moves outward associated with on the one hand, the action of surface tension forces and, on the other, the rate of surface destruction due to the coming together of surfaces. If surface destruction dominates then the fluid elements to which the surface viscous stress boundary condition applies will become part of the fluid interior before diffusion has carried significant vorticity away from the surface. © 1995 American Institute of Physics.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.868524

Permalink

Bibliothek	Standort	Signatur	Band/Heft/Jahr	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

4

Digitale Medien

Tornado forum (1976)

MORTON, B. R. ; SMITH, R. K. ; MCINTYRE, M. E.

[s.l.] : Nature Publishing Group

Nature 260 (1976), S. 457-458

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1476-4687

Quelle: Nature Archives 1869 - 2009

Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik

Notizen: [Auszug] WE believe that the mechanism for vorticity generation and accumulation in the atmosphere proposed by Isaacs et al. is based on misconceptions about the nature of vorticity. The atmosphere contains background vorticity arising from the rotation of the Earth and relative vorticity from weather ...

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1038/260457c0

Permalink

Bibliothek	Standort	Signatur	Band/Heft/Jahr	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

5

Digitale Medien

Steady two-dimensional flow past a normal flat plate (1991)

Ingham, D. B. ; Tang, T. ; Morton, B. R.

Springer

Zeitschrift für angewandte Mathematik und Physik 42 (1991), S. 584-604

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1420-9039

Quelle: Springer Online Journal Archives 1860-2000

Thema: Mathematik , Physik

Notizen: Abstract A vorticity/stream function formulation is used to obtain a numerical simulation of steady two-dimensional flow of a viscous incompressible fluid past a normal flat plate for a range of Reynolds numbers. A method of Fornberg [J. Fluid Mech. 98, 819 (1980)] is used to determine upstream and downstream boundary conditions on the stream function. Special care is taken in the neighbourhood of the singularities in vorticity at the plate edges and this is very important because any errors introduced are swept downstream and severely affect such quantities as the length and width of the attached eddies. The computed results are compared with those of a laboratory experiment in which a plane strip is drawn through water and ethylene glycol for the range of Reynolds numbers for which the experimental flow is stable.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00946178

Permalink

Bibliothek	Standort	Signatur	Band/Heft/Jahr	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext