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| Author | : Robert Edward Spall |
| Publisher | : |
| Total Pages | : 268 |
| Release | : 1987 |
| Genre | : Fluid mechanics |
| ISBN | : |
| Author | : H. L. Chen |
| Publisher | : |
| Total Pages | : 68 |
| Release | : 1991 |
| Genre | : Vortex motion |
| ISBN | : |
In the present study, generation of two vortex rings and their cut-and-connect process were numerically simulated by solving three-dimensional and time-dependent Navier-Stokes equations, under conditions similar to the laboratory experiment. In order to explain the mechanism of cut-and-connect, velocity, vorticity, pressure, helicity density and energy dissipation were examined for the flow field of the cut-and-connect of vortex rings. The present study revealed that energy dissipation is an essential process for circulation cancellation during vortex tubes cutting. Based on this energy dissipation mechanism, it is concluded that the cut-and-connect of vortex tubes may occur in the limit of inviscid flows. This conclusion is particularly important to the three-dimensional discrete vortex method for computing high Reynolds number flows. Features of helicity in the three-dimensional flow field of cut-and-connect process of vortex tubes were also investigated. The relation between the helicity density and the energy dissipation function in the three-dimensional flow field was examined.
| Author | : Keith Vincent Lucas |
| Publisher | : |
| Total Pages | : 306 |
| Release | : 1997 |
| Genre | : |
| ISBN | : |
| Author | : C.H. Liu |
| Publisher | : |
| Total Pages | : |
| Release | : 1989 |
| Genre | : |
| ISBN | : |
| Author | : Y. Nakamura |
| Publisher | : |
| Total Pages | : 20 |
| Release | : 1983 |
| Genre | : Numerical analysis |
| ISBN | : |
The vortex-filament method was applied to the simulation of vortex breakdown. The principal vortex region was represented by multiple filaments, and an axial velocity component was induced by a spiral winding of the filaments. First, an accuracy check was performed for a cylindrical swirling flow field that can be simulated to any accuracy by increasing the number of filaments. Second, an axisymmetric-type vortex breakdown was simulated, with experimental data serving asupstream conditions. The calculated axial- and theta-velocity contours show the breakdown of the vortex, including a rapid change in the vortex core, followed axially by a recovery zone and then a second breakdown. When three-dimensional initial data are used the second breakdown appears to be out of the spiral type in correspondence with experimental observations. The present method can easily be used to simulate other types of vortex breakdown or other vortex flows with axial velocity.
| Author | : |
| Publisher | : |
| Total Pages | : 78 |
| Release | : 1990 |
| Genre | : |
| ISBN | : |
| Author | : |
| Publisher | : |
| Total Pages | : 19 |
| Release | : 1978 |
| Genre | : |
| ISBN | : |
Vortex breakdown is simulated by a three dimensional Lagrangian method using vortex filaments. The filaments are approximated by vortex elements and their velocity is computed by a Biot-Savart type law of interaction. The numerical calculations show the development of an axisymmetric bubble with a recirculation zone and resemble in many respects the results obtained in the physical experiments on vortex breakdown.
| Author | : |
| Publisher | : |
| Total Pages | : 108 |
| Release | : 1976 |
| Genre | : |
| ISBN | : |
| Author | : Thomas John |
| Publisher | : |
| Total Pages | : 210 |
| Release | : 2001 |
| Genre | : |
| ISBN | : |
| Author | : P. G. Saffman |
| Publisher | : Cambridge University Press |
| Total Pages | : 332 |
| Release | : 1995-02-24 |
| Genre | : Mathematics |
| ISBN | : 9780521477390 |
Vortex dynamics is a natural paradigm for the field of chaotic motion and modern dynamical system theory. However, this volume focuses on those aspects of fluid motion that are primarily controlled by the vorticity and are such that the effects of the other fluid properties are secondary.
