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SUMMARY:MEchanics GAthering –MEGA- Seminar: Variational computation of i
 nvariant solutions in wall-bounded chaotic flows
DTSTART:20240516T161500
DTEND:20240516T171500
DTSTAMP:20260501T111428Z
UID:8cc43fda101bd6b71960bf24e27075e4dcaf26f0bceda49de3e6406c
CATEGORIES:Conferences - Seminars
DESCRIPTION:Omid Ashtari (ECPS\, EPFL)\nAbstract: \nThe dynamics of a ch
 aotic fluid flow is supported by invariant solutions embedded in the chaot
 ic attractor of the system. These are non-chaotic solutions to the governi
 ng equations with a simple dependence on time\, such as equilibria and per
 iodic orbits. Despite their significance\, the identification of invariant
  solutions remains a computational challenge\, rendering many solutions in
 accessible.\n\nWe introduce a new family of methods for computing invarian
 t solutions. We recast the computation of an invariant solution as a minim
 ization problem in the space of all sets of the same topological structure
  as the sought-after solution\, e.g.\, the space of all loops when searchi
 ng for a periodic orbit. The deviation of a trial set from satisfying the 
 definition of the objective solution is penalized by a non-negative cost f
 unction. The minimization of the cost function evolves a guess until at a 
 global minimum\, where the cost function takes a value of zero\, an invari
 ant solution is found. This eliminates the need for any time-marching of t
 he flow\, resulting in a robust convergence compared to state-of-the-art m
 ethods.\n\nIn this talk\, the feasibility of the method and its superior c
 onvergence are demonstrated by computing several invariant solutions of th
 e 1D Kuramoto-Sivashinsky dynamics as well as 3D Couette flow.\n\nBio: Om
 id is a PhD candidate at the Emergent Complexity in Physical Systems (ECPS
 ) lab at EPFL. Before joining ECPS\, he completed his B.Sc. and M.Sc. at t
 he University of Tehran\, Iran\, where he specialized in computational flu
 id dynamics. His current research focuses on developing algorithms for non
 linear and chaotic dynamical systems\, aimed at applications in fluid turb
 ulence.
LOCATION:MED 0 1418 https://plan.epfl.ch/?room==MED%200%201418 https://epf
 l.zoom.us/j/67041786969?pwd=a1lXa3lsVGpvL1VpN2RDR2l4clg0QT09
STATUS:CONFIRMED
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