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CATEGORIES:Optimisation and Numerical Analysis Seminars
SUMMARY:Chemical front propagation in periodic flows: FKPP
vs G equation - Alexandra Tzella (School of Mathe
matics\, University of Birmingham)
DTSTART:20171026T110000Z
DTEND:20171026T120000Z
UID:TALK2912AT
URL:/talk/index/2912
DESCRIPTION:We investigate the influence of steady periodic fl
ows on the propagation of chemical pulsating front
s evolving inside an infinite channel domain. We f
ocus on the sharp front arising in Fisher--Kolm
ogorov--Petrovskii--Piskunov (FKPP) type models i
n the limit of small molecular diffusivity and fas
t reaction i.e.\, when the Peclet and Damkohler nu
mbers are large\, and its commonly used heuristic
approximation by the G equation.\nWe use a variati
onal approach to express the two front speeds in t
erms of periodic trajectories that minimise the ti
me of travel across the period of the flow. We sho
w that the only difference lies in the nature of t
he constraint from where we deduce that the front
speed associated with the FKPP equation is greate
r than or equal to the front speed associated wit
h the G equation. We use numerical optimisation to
evaluate the two front speeds for a class of cell
ular vortex flows widely used in experiments. Thes
e computations are verified against closed-form ex
pressions for the archetypal cellular flow.\n
LOCATION:Arts Building\, LR5
CONTACT:Sergey Sergeev
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