T.S.Krasnopolskaya, V.V.Meleshko Laminar stirring of fluids. Part 2. Periodical Stokes flows in wedge annular cavity |
Applied hydromechanics, Vol. 6 (78) ¹ 4, (2004) |
| The paper describes the new methodology for investigating and evaluating the basic properties of distributive laminar mixing in creeping flows [1] by analysing a periodic flow in a wedge annular cavity. The study is based on the construction of Eulerian and Lagrangian representations of mixing process, determination of periodic points, and quantification of the mixed state. It addresses problems: how to organize steady or periodic distributive mixing in a two-dimensional wedge cavity (a prototype for an extruder mixer) and where to put a blob (or blobs) in order to achieve the best result of mixing in finite time. The central question is what determines coherent structures in mixing patterns. Numerical data are presented showing the change in time of the statistical values of the square density, the entropy and the intensity of segregation. These data permit to estimate the dynamics of mixing and deviation from a uniform state at any moment in time. Time reversibility is an important issue in numerical simulations, it concerns the reversibility both of individual points and quality measures. We have concluded that computation of the measures shows a complete reversibility in spite of irreversibility of some individual points. |
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| TEXT LANGUAGE: Russian |