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CATEGORIES:Isaac Newton Institute Seminar Series
SUMMARY:Fast Boundary Element solvers in the frequency dom
ain to simulate coupled acoustic-elastic problems
in the time domain. Application to the simulation
of underwater explosions - Stephanie Chaillat-Lose
ille (CNRS (Centre national de la recherche scient
ifique))
DTSTART;TZID=Europe/London:20230421T110000
DTEND;TZID=Europe/London:20230421T114500
UID:TALK198766AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/198766
DESCRIPTION:Assessing the impact of a remote underwater explos
ion on a submerged structure (submarine) is an imp
ortant naval engineering problem. An underwater ex
plosion mainly induces two distinct phenomena: a &
rdquo\;shock wave&rdquo\; followed by an oscillati
ng bubble of gas. I will concentrate on the modeli
ng of the shock wave in this talk.\n3D rapid trans
ient acoustic problems are known to be difficult t
o solve numerically when dealing with large geomet
ries\, because numerical methods based on geometry
discretisation\, such as the BEM or the FEM\, oft
en require to solve a linear system (from the spac
ial discretisation) for each time step. In a first
part\, I will present \; a numerical method t
o efficiently deal with 3D rapid transient acousti
c problems set in large exterior domains. Using th
e Z-transform and the convolution quadrature metho
d (CQM)\, a straightforward way to reframe the pro
blem to the solving of a large amount of frequency
-domain BEMs is derived. Then\, taking advantage o
f a well-designed high-frequency approximation (HF
A)\, the number of frequency-domain BEMs to be sol
ved is drastically reduced\, with little loss of a
ccuracy. In a second part\, I will discuss how to
consider the FSI problem. A first approach \;
consists in iteratively solving the BEM-FEM coupli
ng by alternating Neumann solutions in each domain
. Unfortunately this simple approach fails. We can
show that the transient BEM-FEM coupling based on
Neumann-Neumann iterations is problematic since e
nergy estimates indicate that each iteration degra
des the regularity of boundary traces (unlike in t
he elliptic case). To avoid this issue\, an iterat
ive algorithm based on Robin boundary conditions f
or the coupled elastodynamic/acoustic problem will
be presented and proved to converge.\nThis is a j
oin work with M. Bonnet\, A. Nassor and D. Mavalei
x-Marchessoux
LOCATION:Seminar Room 1\, Newton Institute
CONTACT:
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