6,710 research outputs found
Interface Problems for Dispersive equations
The interface problem for the linear Schr\"odinger equation in
one-dimensional piecewise homogeneous domains is examined by providing an
explicit solution in each domain. The location of the interfaces is known and
the continuity of the wave function and a jump in their derivative at the
interface are the only conditions imposed. The problem of two semi-infinite
domains and that of two finite-sized domains are examined in detail. The
problem and the method considered here extend that of an earlier paper by
Deconinck, Pelloni and Sheils (2014). The dispersive nature of the problem
presents additional difficulties that are addressed here.Comment: 18 pages, 6 figures. arXiv admin note: text overlap with
arXiv:1402.3007, Studies in Applied Mathematics 201
Fractal homogenization of multiscale interface problems
Inspired by continuum mechanical contact problems with geological fault
networks, we consider elliptic second order differential equations with jump
conditions on a sequence of multiscale networks of interfaces with a finite
number of non-separating scales. Our aim is to derive and analyze a description
of the asymptotic limit of infinitely many scales in order to quantify the
effect of resolving the network only up to some finite number of interfaces and
to consider all further effects as homogeneous. As classical homogenization
techniques are not suited for this kind of geometrical setting, we suggest a
new concept, called fractal homogenization, to derive and analyze an asymptotic
limit problem from a corresponding sequence of finite-scale interface problems.
We provide an intuitive characterization of the corresponding fractal solution
space in terms of generalized jumps and gradients together with continuous
embeddings into L2 and Hs, s<1/2. We show existence and uniqueness of the
solution of the asymptotic limit problem and exponential convergence of the
approximating finite-scale solutions. Computational experiments involving a
related numerical homogenization technique illustrate our theoretical findings
Hybridized CutFEM for Elliptic Interface Problems
We design and analyze a hybridized cut finite element method for elliptic
interface problems. In this method very general meshes can be coupled over
internal unfitted interfaces, through a skeletal variable, using a Nitsche type
approach. We discuss how optimal error estimates for the method are obtained
using the tools of cut finite element methods and prove a condition number
estimate for the Schur complement. Finally, we present illustrating numerical
examples
HPC compact quasi-Newton algorithm for interface problems
In this work we present a robust interface coupling algorithm called Compact
Interface quasi-Newton (CIQN). It is designed for computationally intensive
applications using an MPI multi-code partitioned scheme. The algorithm allows
to reuse information from previous time steps, feature that has been previously
proposed to accelerate convergence. Through algebraic manipulation, an
efficient usage of the computational resources is achieved by: avoiding
construction of dense matrices and reduce every multiplication to a
matrix-vector product and reusing the computationally expensive loops. This
leads to a compact version of the original quasi-Newton algorithm. Altogether
with an efficient communication, in this paper we show an efficient scalability
up to 4800 cores. Three examples with qualitatively different dynamics are
shown to prove that the algorithm can efficiently deal with added mass
instability and two-field coupled problems. We also show how reusing histories
and filtering does not necessarily makes a more robust scheme and, finally, we
prove the necessity of this HPC version of the algorithm. The novelty of this
article lies in the HPC focused implementation of the algorithm, detailing how
to fuse and combine the composing blocks to obtain an scalable MPI
implementation. Such an implementation is mandatory in large scale cases, for
which the contact surface cannot be stored in a single computational node, or
the number of contact nodes is not negligible compared with the size of the
domain. \c{opyright} Elsevier. This manuscript version is made available
under the CC-BY-NC-ND 4.0 license
http://creativecommons.org/licenses/by-nc-nd/4.0/Comment: 33 pages: 23 manuscript, 10 appendix. 16 figures: 4 manuscript, 12
appendix. 10 Tables: 3 manuscript, 7 appendi
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