Vortex dynamics of fiber-laden free shear flows

2005 ◽  
Vol 127 (2-3) ◽  
pp. 73-87 ◽  
Author(s):  
F. Sharifi ◽  
J. Azaiez
Keyword(s):  
Vortex Dynamics ◽  
Shear Flows

Vortices evolution in ideal (M)HD

2021 ◽  
Author(s):  
José Roberto Canivete Cuissa ◽  
Oskar Steiner
Keyword(s):  
Evolution Equation ◽  
Solar Atmosphere ◽  
Vortex Dynamics ◽  
Shear Flows ◽  
Dynamical Equation ◽  
Space Plasma ◽  
Optimal Criterion ◽  
Swirling Strength ◽  
Vortex Tubes

<p>Vortices and vortex tubes are ubiquitous in the solar atmosphere and space plasma. In order to identify vortices and to study their evolution, we seek a suitable mathematical criterium for which a dynamical equation exists. So far, the only option available is given by the vorticity, which however is not the optimal criterion since it can be biased by shear flows. Therefore, we look at another criterion, the swirling strength, for which we found an evolution equation, which we suggest as a novel tool for the analysis of vortex dynamics in (magneto-)hydrodynamics. We highlight a few results obtained by applying the swirling strength and its dynamical equation to simulations of the solar atmosphere.</p>

Vorticity and Vortex Dynamics in Complex Turbulent Flows

1987 ◽  
Vol 11 (1) ◽  
pp. 21-35 ◽  
Author(s):  
J.C.R. Hunt
Keyword(s):  
Turbulent Flows ◽  
Vortex Dynamics ◽  
Shear Flows ◽  
Two Dimensional ◽  
Basic Principles ◽  
New Ideas ◽  
Simple Class ◽  
Basic Equations ◽  
Mixing Length Theory ◽  
Line Elements

Some of the basic principles of vortex dynamics arc reviewed in this paper and applied to calculating and understanding various kinds of turbulent flows. After setting out the basic equations and boundary conditions, the different principles are illustrated for special eases where different simplifications are justified. The displacement of two-dimensional vorticity is applied to two-dimensional shear flows over slender shapes (such as humps or hills on surfaces where the ‘triple-deck’ method is explained in terms of vorticity). The general changes of vorticity and velocity are related to the movement of fluid-line elements. A new geometrical proof for the changes in velocity is given. These concepts are applied to distorted turbulent flows (isotropic and anisotropic) and shear flows. Recent results on the forces on and motions of finite fluid volumes in rotational, non-uniform flows are reviewed and it is shown that the inertial or added mass effects are generally of greater importance than the distortion of the vorticity field. This gives some new insight into Prandtl’s mixing length theory. A simple class of interaction between vortices is reviewed to illustrate how the interactions differ depending on the relative strengths of the vortices. Finally, some new ideas are reviewed on vorticity shed from surfaces and how this interacts with vorticity advected onto a body from upstream.

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