Results 251 to 260 of about 376,528 (290)

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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Numerical and theoretical study on ‘vortex breakdown’

International Journal of Computer Mathematics, 2011
Through our extensive theoretical and numerical study, we present two theorems on vortex tubes and one corollary on ‘vortex breakdown’. First, we addressed that vortex cannot have ends inside the flow field and the only vortex tube that exists inside the flow field is the ring-like vortex with or without legs on the wall. In addition, we found that the
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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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The Nonlinear Stability of Vortex Flows and Vortex Breakdown

1994
On the condition of zero gradient in z direction\((\partial \,/\,\partial \,z = 0)\), a new model is proposed for the study on the stability of vortex motion. One beneficial character of the model is that two of the three vorticity transport equations, in fact, become linear, but the stretching of vorticity is still an essential mechanism.
S. J. Tang, F. G. Zhuang, T. D. Hsing
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The Vortex Breakdown of a Columnar Vortex with Axial Flow

2007
The vortex breakdown of a columnar vortex with axial flow (q-vortex[1]) is investigated numerically. The formation of turbulent eddies around the columnar vortex and the vortex-core deformations are studied in detail by visualizing the flow field. In the marginally stable case with q = -1.5, small thin spiral structures are formed inside the vortex ...
N. Takahashi, T. Miyazaki
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Criterion for vortex breakdown on shock wave and streamwise vortex interactions

Physical Review E, 2014
The interactions between supersonic streamwise vortices and oblique shock waves are theoretically and numerically investigated by three-dimensional (3D) Navier-Stokes equations. Based on the two inequalities, a criterion for shock-induced breakdown of the streamwise vortex is proposed.
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A contribution to the problem of vortex breakdown

Computers & Fluids, 1985
Abstract Associated with the breakdown process is the formation of a stagnation point on the axis of the vortex. This requires the deceleration of the axial velocity component, which must be enforced by a positive axial pressure gradient. The analysis presented here shows, how the pressure gradient along the axis of the vortex is influenced by the ...
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Vortex Breakdown-Tail Interaction

AIAA Journal, 2003
Kim, Y, Rockwell, D, Ozgoren, M
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Vortex breakdown and turbulence

33rd Aerospace Sciences Meeting and Exhibit, 1995
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Intermittent breakdown of the tip leakage vortex and the resultant flow unsteadiness in the tip-region of a subsonic compressor cascade

Aerospace Science and Technology, 2021
Fan Yang, Stephen Spence
exaly