Andrey Aleksyuk - Local description of the three-dimensional wake transition
| Dates: | 12 May 2021 |
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| Times: | 14:00 - 15:00 |
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| What is it: | Seminar |
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| Organiser: | Department of Mathematics |
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| Who is it for: | University staff, External researchers, Current University students |
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Andrey Aleksyuk (University of Manchester) joins us for this virtual seminar in the Physical Applied Mathematics Series
This seminar will be held via Zoom. Please email chris.johnson@manchester.ac.uk if you require the meeting details.
Abstract:
For a wide class of flows, three-dimensionality occurs as a result of a 2D base flow instability. The flow may contain several interacting regions of perturbations development, which makes it difficult to determine the true nature of 3D structures. This situation is typical for the canonical problem of a flow around a cylindrical body, for which various modes of 3D instability are observed, depending on the flow conditions (body shape, external influences). For example, mode A develops in the forming vortices and in the braid shear layers. However, it is unclear which of these interacting local features undergoes instability and causes the emergence of three-dimensionality. The present study aims to clarify the physical mechanisms leading to the appearance of three-dimensionality in such flows. The evolution of 3D vortex structures is simulated by the numerical solution of the Navier–Stokes equations. The influence of basic mechanisms (such as vorticity diffusion, stretching and tilting of vortex lines) on the growth and decay of perturbations in fluid particles is shown. The viability of some simplified theoretical models for perturbation development in forming vortices and braid shear layers is discussed.
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