Results 121 to 130 of about 6,551 (166)

Vortex development and breakdown

8th Fluid and PlasmaDynamics Conference, 1975
Abstract : A line vortex is assumed to consist of a thin viscous core of laminar embedded in an inviscid flow of uniform circulation and with axial velocity that may depend upon the distance along the core. Self-similar solutions are obtained for the particular case of an external velocity inversely proportional to the core length.
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Vortex breakdown in spherical gap

The Physics of Fluids, 1987
A finite element solution of the flow between rotating spheres shows a vortex breakdown for Reynolds numbers exceeding a critical value. The result is in agreement with published results for a vortex breakdown in a cylindrical enclosure.
P. Bar-Yoseph, S. Seelig, A. Solan, K. G. Roesner   +3 more
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Numerical study of vortex breakdown

24th Aerospace Sciences Meeting, 1986
The incompressible axisymmetric steady Navier-Stokes equations and the Euler equations are solved numerically to model the breakdown of a vortex. The solutions obtained for the Euler equations show a 'vortex breakdown-like' structure, their behavior is very different from that of the Navier-Stokes solutions which are obtained at low Reynolds number ...
Hafez, M., Kuruvila, G., Salas, M. D.
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Vortex Breakdown in Swirling Conical Flows

AIAA Journal, 1971
This paper describes some experiments in swirling flows in a mildly diverging cylindrical tube in which three types of vortex breakdown were observed: double-helix and spiral forms (followed by turbulent mixing), and axisymmetric form (often followed by a spiral breakdown, then by turbulent mixing). The type and location of the breakdowns were found to
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Research into vortex breakdown control

Progress in Aerospace Sciences, 2001
Abstract Vortex breakdown remains a significant and intriguing phenomenon that can have detrimental or beneficial effects, depending on the application. Thus there is a strong need to both better understand the phenomenon and to control it, either to prevent breakdown or to promote it.
Anthony M Mitchell, Jean Délery
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Vortex Breakdown

Abstract A thin vortex tube can undergo a sudden expansion, often leading to instability and turbulence, if subject to an external deceleration. This is called vortex breakdown, and it is often observed in swirling flow in a slowly diverging pipe, and in the scroll vortices that develop on the upper surface of a delta wing.
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Computational Studies of Vortex Breakdown

1992
Abstract : Axisymmetric vortex breakdown was simulated numerically within an enclosed circular cylinder with: (1) fixed cylindrical wall-endwall and one rotating lid; and (2) rotating cylindrical wall-endwall with a differentially rotating lid. Variations of the two dynamical parameters permitted the calculation of cases in which incipient vortex ...
John P. Watson, G. P. Neitzel
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Vortex Breakdown as a Catastrophe

1998
By studying swirling viscous jets, we develop a new explanation of vortex breakdown, show how solution non-uniqueness appears through cusp and fold catastrophes as the Reynolds number Re increases, and obtain analytical solutions for Re → ∞. Although inviscid theories also involve fold catastrophe, they have a strong limitation: the dependence of the ...
Vladimir Shtern, Fazle Hussain
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The Structure of Vortex Breakdown

Annual Review of Fluid Mechanics, 1978
The term 'vortex breakdown', as used in the reported investigation, refers to a disturbance characterized by the formation of an internal stagnation point on the vortex axis, followed by reversed flow in a region of limited axial extent. Two forms of vortex breakdown, which predominate, are shown in photographs.
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Some Experiments with Vortex Breakdown

The Journal of the Royal Aeronautical Society, 1964
SummaryWater tunnel flow visualisation experiments on a slender delta wing have revealed some new phenomena connected with vortex breakdown. Vortex breakdown hysteresis has been found, there being two steady flow states at some incidences, one with breakdown on the wing and one without. The formation of vortex breakdown has been studied and found to be
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