bioRxiv (Cold Spring Harbor Laboratory),
Год журнала:
2024,
Номер
unknown
Опубликована: Авг. 16, 2024
Abstract
Hepatic
vascular
hemodynamics
is
an
important
reference
indicator
in
the
diagnosis
and
treatment
of
hepatic
diseases.
However,
Method
based
on
Computational
Fluid
Dynamics(CFD)
are
difficult
to
promote
clinical
applications
due
their
computational
complexity.
To
this
end,
study
proposed
a
deep
graph
neural
network
model
simulate
one-dimensional
hemodynamic
results
vessels.
By
connecting
residuals
between
edges
nodes,
framework
effectively
enhances
prediction
accuracy
efficiently
avoids
over-smoothing
phenomena.
The
structure
constructed
from
centerline
boundary
conditions
vasculature
can
serve
as
input,
yielding
velocity
pressure
information
corresponding
centerline.
Experimental
indicate
that
our
method
achieves
higher
dataset
with
significant
individual
variations
be
extended
involving
other
blood
Following
training,
errors
both
fields
maintained
below
1.5%.
trained
easily
deployed
low-performance
devices
and,
compared
CFD-based
methods,
output
along
vessel
at
speed
three
orders
magnitude
faster.
Author
summary
When
using
learning
methods
for
analysis,
simple
point
cloud
data
cannot
express
real
geometric
vessels,
it
necessary
have
additional
extraction
capability.
In
paper,
we
use
predict
parameters.
vessels
topology
branch
which
improve
strong
generalisation
ability.
show
highest
flow
simulation
dataset,
experimental
human
aorta
also
applied
organs.
Physics-informed
neural
networks
(PINNs)
are
widely
used
to
solve
forward
and
inverse
problems
in
fluid
mechanics.
However,
the
current
PINNs
framework
faces
notable
challenges
when
presented
with
that
involve
large
spatiotemporal
domains
or
high
Reynolds
numbers,
leading
hyper-parameter
tuning
difficulties
excessively
long
training
times.
To
overcome
these
issues
enhance
PINNs'
efficacy
solving
problems,
this
paper
proposes
a
parallel
physics-informed
(STPINNs)
can
be
deployed
simultaneously
multi-central
processing
units.
The
STPINNs
is
specially
designed
for
of
mechanics
by
utilizing
an
overlapping
domain
decomposition
strategy
incorporating
Reynolds-averaged
Navier–Stokes
equations,
eddy
viscosity
output
layer
networks.
performance
proposed
evaluated
on
three
turbulent
cases:
wake
flow
two-dimensional
cylinder,
homogeneous
isotropic
decaying
turbulence,
average
three-dimensional
cylinder.
All
cases
successfully
reconstructed
sparse
observations.
quantitative
results
along
strong
weak
scaling
analyses
demonstrate
accurately
efficiently
flows
comparatively
numbers.
The
flow-field
reconstruction
of
a
rotating
detonation
combustor
(RDC)
is
essential
to
understand
the
stability
mechanism
and
performance
engines.
This
study
embeds
reduced-order
model
an
RDC
into
neural
network
(NN)
construct
physics-informed
(PINN)
achieve
full-dimensional
high-resolution
flow
field
based
on
partially
observed
data.
Additionally,
unobserved
physical
fields
are
extrapolated
through
NN-embedded
model.
influence
residual
point
sampling
strategy
observation
spatial-temporal
resolution
results
studied.
As
surrogate
RDC,
PINN
fills
gap
that
traditional
computational
fluid
dynamics
methods
have
difficulty
solving,
such
as
inverse
problems,
has
engineering
value
for
RDCs.
Supervised
deep
learning
methods
reported
recently
have
shown
promising
capability
and
efficiency
in
particle
image
velocimetry
(PIV)
processes
compared
to
the
traditional
cross
correlation
optical
flow
methods.
However,
learning-based
previous
reports
require
synthesized
images
simulated
flows
for
training
prior
applications,
conflicting
with
experimental
scenarios.
To
address
this
crucial
limitation,
unsupervised
also
been
proposed
velocity
reconstruction,
but
they
are
generally
limited
rough
reconstructions
low
accuracy
due
to,
example,
occlusion
out-of-boundary
motions.
This
paper
proposes
a
new
model
named
UnPWCNet-PIV
(an
network
using
Pyramid,
Warping,
Cost
Volume).
Such
pyramidical
specific
enhancements
on
holds
capabilities
manage
boundary
The
showed
comparable
robustness
advanced
supervised
methods,
which
based
images,
together
superior
performance
images.
presents
details
of
architecture
assessments
its
both
Artificial
intelligence
based
on
neural
network
technology
has
provided
innovative
methods
for
predicting
unsteady
flow
fields.
However,
both
purely
data-driven
and
single
physics-driven
can
only
perform
short-term
predictions
fields
are
unable
to
achieve
medium-
long-term
predictions.
A
composite
CNN-GRU-PINN
(CGPINN)
is
proposed
by
combining
convolutional
(CNN),
gated
recurrent
unit
(GRU),
physics-informed
(PINN).
CNN
GRU
used
learn
the
spatial
temporal
characteristics
of
flows,
respectively.
PINN
adopted
constrain
field
prediction
data
according
physical
laws.
The
around
a
circular
cylinder
employed
verify
performances
CGPINN.
test
results
show
that
compared
PINN,
reconstruction
accuracy
CGPINN
improved
about
86.10%
average,
96.18%.
Compared
pure
approaches,
an
average
65.71%.
Additionally,
exhibits
better
robustness,
demonstrating
insensitivity
variations
in
sample
size
noise
levels,
thereby
ensuring
stable
reliable
across
diverse
conditions.
This
study
more
accurate
robust
method
Journal of Offshore Mechanics and Arctic Engineering,
Год журнала:
2024,
Номер
146(6)
Опубликована: Авг. 1, 2024
Abstract
Flow-induced
vibration
(FIV)
is
a
common
phenomenon
in
ocean
engineering
for
subsea
structures
with
circular-shaped
cross
sections.
A
large
amount
of
computational
resources
or
experimental
efforts
are
required
to
predict
measure
the
complicated
motions
and
flow
field
surrounding
circular
cylinder
undergoing
vortex-induced
(VIV).
Physics-informed
neural
networks
(PINNs)
powerful
deep
learning
techniques
solving
governing
partial
differential
equations
(PDEs)
dynamic
systems
as
an
alternative
complex
numerical
methods.
In
present
study,
framework
built
employing
PINNs
Navier–Stokes
flows
past
FIV
using
sparsely
distributed
spatiotemporal
data
inside
domain.
The
training
process
involves
minimizing
supervised
loss
at
these
sparse
points
residuals
PDEs.
For
PINN
model,
moving
frame
around
used
collect
from
two-dimensional
direct
simulation
results
low
Reynolds
number.
structural
displacements
also
implemented
developed
PINN.
performance
evaluated
by
comparing
predicted
contours
velocities
data.
hydrodynamic
forces
prediction
achieved
PINN-obtained
predictions
combined
force
partitioning
method.