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CATEGORIES:Laboratory for Scientific Computing
SUMMARY:A conservative level-set based method for multi-co
mponents problems on fixed grids - Ben Obadia (Cra
nfield University)
DTSTART;TZID=Europe/London:20120203T110000
DTEND;TZID=Europe/London:20120203T123000
UID:TALK36673AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/36673
DESCRIPTION:A three-dimensional Eulerian method is presented f
or the simulation of multi-components flows\, from
shock impacts between compressible fluids to flui
d-structure interaction\, with elastic-plastic def
ormations. The main purpose of that numerical meth
od is to cope with the issues usually encountered
during such interactions:\n\n- keeping a sharp int
erface even when large deformations occur during i
mpacts problems\;\n\n- nonlinear wave-propagation
in the different media\;\n\n- accurate modeling of
the constitutive properties of the solid medium u
nder strong shock\, and calculation of its elasto-
plastic behavior in an Eulerian frame.\n\nThe inte
rface tracking between materials relies on the use
of level-set functions. A new conservative techni
que has been developed\, where cut-cells at the in
terface are identified and treated specifically. A
s such cells might have extremely small volume fra
ctions\, the CFL condition required for stability
might become extremely small as well\, driving the
simulation to a potentially infinitely long compu
tational time. To overcome this problem\, a mass\,
momentum\, and energy redistribution among the ne
ighboring cells is used\, ensuring simultaneously
conservation. This approach had been previously in
vestigated and implemented in 2D\, and is here ext
ended to 3D.\n\nEach phase\, except at the neighbo
urhood of the interface\, is treated independently
with traditional shock-capturing schemes. High-or
der accuracy is achieved by incorporating the weig
hted-essentially non-oscillatory (WENO) method\, a
nd Runge-Kutta time integration. For solid/fluid p
roblems\, a dedicated Riemann solver has also been
developed to comply to the interface treatment.\n
\nThis whole numerical scheme is demonstrated usin
g 1D\, 2D and 3D calculations. This includes initi
al values problems for 1D testcases\, whilst the 2
D and 3D problems come essentially from previous n
umerical studies\, whether for strong fluid/fluid
and fluid/solid interaction.
LOCATION:Seminar Room B\, Rutherford Building\, Cavendish L
aboratory
CONTACT:Dr Nikolaos Nikiforakis
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