scispace - formally typeset
Search or ask a question
Topic

Starting vortex

About: Starting vortex is a research topic. Over the lifetime, 4785 publications have been published within this topic receiving 100419 citations.


Papers
More filters
Journal ArticleDOI
TL;DR: In this article, the growth of a line vortex with time and the spread of a trailing vortex behind a wing due to turbulence are considered, and it is shown that the eddy viscosity for this type of motion may be taken to be proportional to the circulation round the vortex and the solution is then similar to the solution for the growing of a vortex in laminar flow.
Abstract: The growth of a line vortex with time and the spread of a trailing vortex behind a wing due to turbulence are considered. It is shown that the eddy viscosity for this type of motion may be taken to be proportional to the circulation round the vortex and the solution is then similar to the solution for the growth of a vortex in laminar flow. The method is applied to calculate the distance behind a wing for which the trailing vortices will touch one another.

187 citations

Journal ArticleDOI
TL;DR: In this article, a fresh look at the vortical structures of JICF in water by releasing dye at strategic locations around the jet exit was taken, and it was shown that there is no evidence of ring vortices in cross flow and the postulation that vortex loops are formed from the folding of the vortex rings does not reflect the actual flow behavior.
Abstract: It is well known that vortex rings are the dominant flow structures in the near field of a free jet, and this has led many researchers to believe that they also occur in a jet in cross flow (JICF). Previous studies have postulated that these vortex rings deform and fold as they convect downstream, which culminates in the formation of vortex loops at both the upstream and the lee-side of the jet column. In this paper, we take a fresh look at the vortical structures of JICF in water by releasing dye at strategic locations around the jet exit. The results show that there is no evidence of ring vortices in JICF, and the postulation that vortex loops are formed from the folding of the vortex rings does not reflect the actual flow behavior. The presence of a counter-rotating vortex pair (CVP) at the jet exit is found to inhibit the formation of the vortex rings. Instead, vortex loops are formed directly from the deformation of the cylindrical vortex sheet or jet column, without going through the vortex rings, in a process similar to the buoyant jet and wake structures studied by Perry and Lim [J. Fluid Mech. 88, 451 (1978)].

186 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated the effect of airfoil stiffness on the strength and force of the induced jet induced by a hovering aircraft at zero-freestream velocity.
Abstract: Thrust generation for an airfoil plunging at zero freestream velocity, the case relevant to hovering birds and insects, has been studied. The objective was to investigate the effect of airfoil stiffness. Particle image velocimetry and force measurements were taken for three airfoils of relative bending stiffnesses 1:8:512 in a water tank. The deformation of the flexible airfoils produces an angle of attack that varies periodically with a phase angle with respect to the plunging motion. Amplitude and phase of this combined plunging/pitching motion play a major role in the flowfield and thrust generation. Vortex pairs or alternating vortex streets were observed depending on the amplitude and phase lag of the trailing edge. The strength of the vortices, their lateral spacing, and the time-averaged velocity of the induced jet were found to depend on the airfoil flexibility, plunge frequency, and amplitude. Direct force measurements confirmed that at high plunge frequencies the thrust coefficient of the airfoil with intermediate stiffness was greatest, although the least stiff airfoil can generate larger thrust at low frequencies. It is suggested that there is an optimum airfoil stiffness for a given plunge frequency and amplitude. The thrust/input-power ratio was found to be greater for the flexible airfoils than for the rigid airfoil.

185 citations

Journal ArticleDOI
TL;DR: In this article, the convergence of a large class of vortex methods for two-dimensional incompressible, inviscid flows with Holder continuous initial data was proved and several infinite order methods were presented.
Abstract: We prove the convergence of a large class of vortex methods for two-dimensional incompressible, inviscid flows with Holder continuous initial data. We present several infinite order methods and est...

183 citations


Network Information
Related Topics (5)
Reynolds number
68.4K papers, 1.6M citations
92% related
Boundary layer
64.9K papers, 1.4M citations
90% related
Vortex
72.3K papers, 1.3M citations
90% related
Turbulence
112.1K papers, 2.7M citations
89% related
Laminar flow
56K papers, 1.2M citations
87% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202336
202278
20217
20207
20196
201815