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@PHDTHESIS{Helmig:834178,
author = {Helmig, Jan},
othercontributors = {Elgeti, Stefanie Nicole and Behr, Marek and Möller,
Matthias},
title = {{B}oundary-conforming finite element methods for complex
rotating domains},
school = {Rheinisch-Westfälische Technische Hochschule Aachen},
type = {Dissertation},
address = {Aachen},
publisher = {RWTH Aachen University},
reportid = {RWTH-2021-09694},
pages = {1 Online-Ressource : Illustrationen},
year = {2021},
note = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
University 2022; Dissertation, Rheinisch-Westfälische
Technische Hochschule Aachen, 2021},
abstract = {Simulation technology has become a very powerful tool to
describe and predict physical processes like complex flow.
Many of these simulation techniques – and among those the
finite element method (FEM) – require the generation of a
discrete version of the domain of interest, the
computational mesh. Such meshes cannot be chosen
arbitrarily, but have to satisfy certain quality criteria.
Boundary-conforming meshes, which are aligned with the
domain boundary, have significant advantages in terms of
accuracy and efficiency. However, with increasing complexity
of the domain, generating such meshes can be very
time-consuming. This is especially true for applications
with complex moving domains, e.g., caused by rotating parts
and small geometric features. The example considered within
this thesis are twin-screw extruders (TSEs). The particular
challenge for a TSE is the co-rotating deformation of the
computational domain with very small gap sizes between the
individual parts. To allow the use of boundary-conforming
meshes for TSEs with convex screw shapes we develop an
efficient, tailor-made mesh update method. It makes the need
for remeshing and projections of solutions obsolete. In
addition, a spline-based meshing technique that extends the
previously described method to screw shapes of
arbitrarycomplexity is presented. A sliding mesh approach
based on Nitsche’s method to account for discontinuities
of the screw design in axial direction complements both
methods. The proposed meshing concepts are then used to
simulate the flow of polymer melts in TSEs. Mathematical and
numerical models describing such flows are also discussed.
This includes non-Newtonian models to accurately describe
the flow behavior of polymer melts. 2D and 3D test cases
verify the presented methods including convergence studies
and comparisons with experiments. Furthermore, cases
evaluating complex, unsteady temperature-dependent flow of
polymer melt inside TSEs with multiple screw elements show
the potential of the presented methods to industrial
applications.},
cin = {416010},
ddc = {620},
cid = {$I:(DE-82)416010_20140620$},
typ = {PUB:(DE-HGF)11},
doi = {10.18154/RWTH-2021-09694},
url = {https://publications.rwth-aachen.de/record/834178},
}
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