A.A.Gourjii Fluid stirring in the velocity field of two point vortices behind infinite cylinder in shear flow of ideal fluid |
Applied hydromechanics, Vol. 7 (79) ¹ 1, (2005) |
| The mixing process of a passive fluid (advection) in oncomming flow of an ideal incompressible fluid on an infinite cylinder with circular cross section in a perpendicular direction due to own generatrix is considered. The two-dimensional stirring cases with a presence and an absence of a point vortex pair in the region located nearby the cylinder. Is shown, that there is a stationary motion regime of vortex pair near the cylinder, which is generally unstable for small perturbations. However in case of symmetric perturbation, the vortex motion is steady, and periodic in time. The investigation shows that the mixing process of passive fluid in absence of vortices is regular and is not accompanied by an intensive stretching of border of dyed region under consideration in time. However, the presence of the vortex pair, which moves periodically around an equilibrium point both in front, and behind of the cylinder, leads to an essential changes in stretching process. The stretching of border of dyed passive region becomes an exponential in time, that testifies that an advection regime is intensive and chaotic. The comparison of various mixing modes with the presence of vortex pair nearby the circular cylinder in incomming unperturbated flow of an ideal incompressible liquid is considered in this work. |
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| TEXT LANGUAGE: Russian |