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Numerical Investigations of a Partitioned FSI Algorithm for Tetra Pak's Filling Tube

Andersson, Leo LU (2016) MVK920 20161
Department of Energy Sciences
Abstract
Numerical simulations of fluid-structure interaction of a water-filled tube with a free surface
are conducted using an implicit partitioned coupling scheme. Abaqus and STAR-CCM+ are
used for the solid- and fluid domains respectively. This application has stability issues, with
the most severe turning out to be the added mass effect. Rayleigh β damping and grid flux
under-relaxation has been used to keep simulations stable and these parameters’ effect on the
solution and stability are investigated. A model problem consisting of a completely filled tube of
a linear elastic material and a potential flow is analysed with respect to stability, considering the
HHT time integration scheme used in Abaqus. A criterion for the displacement... (More)
Numerical simulations of fluid-structure interaction of a water-filled tube with a free surface
are conducted using an implicit partitioned coupling scheme. Abaqus and STAR-CCM+ are
used for the solid- and fluid domains respectively. This application has stability issues, with
the most severe turning out to be the added mass effect. Rayleigh β damping and grid flux
under-relaxation has been used to keep simulations stable and these parameters’ effect on the
solution and stability are investigated. A model problem consisting of a completely filled tube of
a linear elastic material and a potential flow is analysed with respect to stability, considering the
HHT time integration scheme used in Abaqus. A criterion for the displacement under-relaxation
factor ω is found, depending on the geometry, material parameters, β and time step. The impact
on stability of changing these parameters is discussed and the stability criterion is validated
against simulations. An effort is made to provide suitable settings and recommendations for
future simulations.
It is found that β damping is very effective in stabilising the algorithm, but changes the solu-
tion significantly. Grid flux under-relaxation also helps stabilise the solution, but the mechanism
is not clear and its effect on the solution is erratic. It turns out that smaller time steps have
a destabilising effect on the partitioned algorithm, and so do long tubes, thin, weak structures
and heavy fluids. The added mass effect can be mitigated by lowering ω, but at the cost of com-
putation time. The results of numerical experiments are in good agreement with the criterion
established by the model problem. Some additional factors influencing stability are discussed,
including viscosity, the effect of an obstructed flow, boundary conditions, a nonlinear finite ele-
ment formulation and a higher order time discretisation scheme. (Less)
Please use this url to cite or link to this publication:
author
Andersson, Leo LU
supervisor
organization
course
MVK920 20161
year
type
H2 - Master's Degree (Two Years)
subject
keywords
fluid-structure interaction, FSI, added mass effect, partitioned implicit scheme, stability, Rayleigh damping, grid flux under-relaxation
report number
LUTMDN/TMHP-16/5368-SE
ISSN
0282-1990
language
English
id
8879486
date added to LUP
2016-06-30 14:38:04
date last changed
2016-06-30 14:38:04
@misc{8879486,
  abstract     = {Numerical simulations of fluid-structure interaction of a water-filled tube with a free surface
are conducted using an implicit partitioned coupling scheme. Abaqus and STAR-CCM+ are
used for the solid- and fluid domains respectively. This application has stability issues, with
the most severe turning out to be the added mass effect. Rayleigh β damping and grid flux
under-relaxation has been used to keep simulations stable and these parameters’ effect on the
solution and stability are investigated. A model problem consisting of a completely filled tube of
a linear elastic material and a potential flow is analysed with respect to stability, considering the
HHT time integration scheme used in Abaqus. A criterion for the displacement under-relaxation
factor ω is found, depending on the geometry, material parameters, β and time step. The impact
on stability of changing these parameters is discussed and the stability criterion is validated
against simulations. An effort is made to provide suitable settings and recommendations for
future simulations.
It is found that β damping is very effective in stabilising the algorithm, but changes the solu-
tion significantly. Grid flux under-relaxation also helps stabilise the solution, but the mechanism
is not clear and its effect on the solution is erratic. It turns out that smaller time steps have
a destabilising effect on the partitioned algorithm, and so do long tubes, thin, weak structures
and heavy fluids. The added mass effect can be mitigated by lowering ω, but at the cost of com-
putation time. The results of numerical experiments are in good agreement with the criterion
established by the model problem. Some additional factors influencing stability are discussed,
including viscosity, the effect of an obstructed flow, boundary conditions, a nonlinear finite ele-
ment formulation and a higher order time discretisation scheme.},
  author       = {Andersson, Leo},
  issn         = {0282-1990},
  keyword      = {fluid-structure interaction,FSI,added mass effect,partitioned implicit scheme,stability,Rayleigh damping,grid flux under-relaxation},
  language     = {eng},
  note         = {Student Paper},
  title        = {Numerical Investigations of a Partitioned FSI Algorithm for Tetra Pak's Filling Tube},
  year         = {2016},
}