| 25/04/2024 | | | | 11h | | | | Salle de conférences | | |
| | Siddhartha Mukherjee (LJAD) | | | | Identifying and disentangling emergent structures in turbulent flows with a generalized correlation-decomposition framework | | | | The organization of turbulent flows, long conceptualized in terms of "coherent structures", has resisted clear description. A significant limitation has been the lack of tools to identify instantaneous, spatially finite structures that arise both in real flow measurements, or in turbulent solutions of the Navier-Stokes equations. We present a framework of generalized correlations aimed at identifying various patterns in flow fields. Coupled with the Helmholtz-decomposition, this provides a paradigm to not just identify, but also disentangle structures from superposition. After examples with lower dimensional vortex-based canonical flows, we apply these tools to turbulence fields obtained from simulations of the Navier-Stokes equation in 3D. We find that high kinetic energy regions form compact velocity-jets, while high vorticity regions form vorticity-jets surrounded by swirling velocity. A full Biot–Savart decomposition of the velocity field shows that these velocity-jets are neither self-induced, nor induced by the interaction of swirling, strong vorticity regions. They are almost entirely induced, non-locally, by the permeating intermediate range vorticity. Velocity-swirls, instead, are a superposition of self-induced and background-induced contributions. Our work suggests that turbulence organization could result from non-local and non-linear field interactions, leading to an emergent description unlike the notion of a strict structural hierarchy. Our correlation-decomposition framework lends itself readily to the study of generic vector and scalar fields associated with diverse phenomena.
| | | | Gestion: Florence |
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| | () | | | | Ecole Semiclassique et Applications (13-17 mai) | | | | | | | | Gestion: Maxime |
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| | Jason Picardo () | | | | TBA | | | | | | | | Gestion: Florence |
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| | Colm Caulfield (University of Cambridge) | | | | Rencontres Niçoises de Méca Flu | | | | | | | | Gestion: Florence |
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| 06/06/2024 | | | | 11h | | | | Salle Fizeau | | |
| | Salma Lahbabi (Université de Casablanca) | | | | | | | | | | |
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| 20/06/2024 | | | | 11h | | | | Salle de conférences | | |
| | Maxime Herda (Université de Lille) | | | | TBA | | | | | | | | Gestion: Isabelle |
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| | David Hughes () | | | | | | | | | | | | Gestion: Florence |
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| | () | | | | DataHyKing Days | | | | | | | | Gestion: Thomas |
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| | André Galligo ? () | | | | | | | | | | | | Gestion: Isabelle |
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