Boundary Vorticity Dynamics at Very Large Reynolds Numbers
During the last century, the theoretical investigations in the boundary vorticity dynamics were based on the concept of a fluid of small-constant viscosity, i.e. the Newtonian fluid, described by the non-slip condition at the wall and the linear law for fluid friction. But the application of curren...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
National Institute for Aerospace Research “Elie Carafoli” - INCAS
2015-09-01
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| Series: | INCAS Bulletin |
| Subjects: | |
| Online Access: | http://bulletin.incas.ro/files/dumitrescu_cardos_malael_vol_7_iss_3.pdf |
| Summary: | During the last century, the theoretical investigations in the boundary vorticity dynamics were based on the concept of a fluid of small-constant viscosity, i.e. the Newtonian fluid, described by
the non-slip condition at the wall and the linear law for fluid friction. But the application of current ideas in non-linear hydrodynamic stability theory to the flow in shear layers showed the existence of a class of flows involving concentrations of vorticity, also visible both in experimental conditions and
industrial environments. The role of concentrated vorticity in fluid dynamics phenomena, concerning both the vorticity creation at the boundary and the response/reaction to the flow field is not entirely understood. The main purpose of this paper is to bring about a better mechanism of vorticity creation at the wall beneath a flow using the concept of thixotropic fluid associated with an active vorticity governed by the vorticity transport equation that is able to react back on the fluid flow. Such a viscoelastic behavior can be easily forecasted by the relationship between the value of the critic Reynolds number, Rec, and the equilibrium kinetic viscosity 2 1 0 0 , Rec e , argued in the sequel by
means of the thixotropic fluid concept. |
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| ISSN: | 2066-8201 2247-4528 |