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UID:8961@i2m.univ-amu.fr
DTSTART;TZID=Europe/Paris:20260324T110000
DTEND;TZID=Europe/Paris:20260324T120000
DTSTAMP:20260317T175954Z
URL:https://www.i2m.univ-amu.fr/evenements/seminaire-aa-tba-14/
SUMMARY:Ksenia Kozhanova (M2P2): Séminaire AA -- Variational Cell-Centered
  Direct ALE Scheme for Compressible Flows: Consistency and Structure Prese
 rvation in the Lagrangian Limit
DESCRIPTION:Ksenia Kozhanova: The numerical simulation of compressible flow
 s on moving meshes poses significant challenges due to the need to simulta
 neously preserve conservation laws\, geometric consistency\,\nand thermody
 namic structure under strong deformation and complex flow regimes. Arbitra
 ry Lagrangian–Eulerian (ALE) methods [1] provide a flexible framework to
  address these\nchallenges\, but maintaining robustness and physical fidel
 ity across the full spectrum from\nEulerian to Lagrangian descriptions rem
 ains difficult.\nIn this work\, we present a variational\, cell-centered A
 LE formulation based on the Ge-\nometry\, Energy\, and Entropy Compatible 
 (GEEC) framework [3]. In this approach\, the\ndiscretization is performed 
 at the level of the underlying fluid Lagrangian\, and the dis-\ncrete evol
 ution equations are obtained through a least-action principle. This constr
 uction\nnaturally enforces key structural properties\, including exact con
 servation of mass\, momentum\, and total energy\, as well as geometric com
 patibility between mesh motion and control\nvolumes and entropy consistenc
 y in the absence of physical dissipation.\nWithin this framework\, particu
 lar attention is given to the interplay between mass trans-\nport and pres
 sure forces\, which are intrinsically coupled through the variational stru
 cture.\nWe discuss the behavior of the scheme in regimes approaching the L
 agrangian limit\, where\nstandard discretizations may exhibit loss of symm
 etry and degraded conservation proper-\nties. A formulation is presented t
 hat maintains consistent pressure coupling and geometric\nconservation und
 er mesh motion\, ensuring stable and physically meaningful behavior even\n
 in strongly deforming configurations [2].\nThe resulting method provides a
  robust and structure-preserving approach for compressible flow simulation
  on arbitrarily moving meshes. Its performance is illustrated on\nrepresen
 tative test cases involving shocks and highly compressive regimes. The fir
 st results\nof these extensions to multi-material and multiphase flows wil
 l also be demonstrated.\n\nReferences\n[1] C. W. Hirt\, A. A. Amsden\, and
  J. L. Cook. An arbitrary Lagrangian–Eulerian computing\nmethod for all 
 flow speeds. J. Comput. Phys.\, 14(3):227–253\, 1974.\n[2] Ksenia Kozhan
 ova\, Gabriel Farag\, Antoine Llor\, Pierre Boivin\, et al. Variational ce
 ll-\ncentered ale scheme for compressible flows: Improved consistency in t
 he lagrangian limit.\nComputers and Fluids\, 2025. Preprint.\n[3] T. Vazqu
 ez-Gonzalez\, A. Llor\, and C. Fochesato. A novel GEEC (Geometry\, Energy\
 , and\nEntropy Compatible) procedure applied to a staggered direct-ALE sch
 eme for hydrodynamics. Eur. J. Mech. B Fluids\, 65:494–514\, 2017.
CATEGORIES:Séminaire,Analyse Appliquée
LOCATION:I2M Saint-Charles - Salle de séminaire\, Université Aix-Marseill
 e\, Campus Saint-Charles\, 3 Place Victor Hugo\, Marseille\, 13003\, Franc
 e
X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=Université Aix-Marseille\,
  Campus Saint-Charles\, 3 Place Victor Hugo\, Marseille\, 13003\, France;X
 -APPLE-RADIUS=100;X-TITLE=I2M Saint-Charles - Salle de séminaire:geo:0,0
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TZID:Europe/Paris
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DTSTART:20251026T020000
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