Physics of Fluids,
Journal Year:
2024,
Volume and Issue:
36(11)
Published: Nov. 1, 2024
Surrogate
models
that
combine
dimensionality
reduction
and
regression
techniques
are
essential
to
reduce
the
need
for
costly
high-fidelity
computational
fluid
dynamics
data.
New
approaches
using
β-variational
autoencoder
(β-VAE)
architectures
have
shown
promise
in
obtaining
high-quality
low-dimensional
representations
of
high-dimensional
flow
data
while
enabling
physical
interpretation
their
latent
spaces.
We
propose
a
surrogate
model
based
on
space
predict
pressure
distributions
transonic
wing
given
flight
conditions:
Mach
number
angle
attack.
The
β-VAE
model,
enhanced
with
principal
component
analysis
(PCA),
maps
space,
showing
direct
correlation
conditions.
Regularization
through
β
requires
careful
tuning
improve
overall
performance,
PCA
preprocessing
helps
construct
an
effective
improving
training
performance.
Gaussian
process
is
used
variables
from
conditions,
robust
behavior
independent
β,
decoder
reconstructs
field
This
pipeline
provides
insight
into
unexplored
Furthermore,
fine-tuning
further
refines
reducing
dependence
enhancing
accuracy.
Structured
significant
improvements
collectively
create
highly
accurate
efficient
model.
Our
methodology
demonstrates
effectiveness
β-VAEs
aerodynamic
modeling,
offering
rapid,
cost-effective,
reliable
alternative
prediction.
Physics of Fluids,
Journal Year:
2024,
Volume and Issue:
36(1)
Published: Jan. 1, 2024
Conducting
large-scale
numerical
computations
to
obtain
flow
field
during
the
hypersonic
vehicle
engineering
design
phase
can
be
excessively
costly.
Although
deep
learning
algorithms
enable
rapid
prediction
with
high-precision,
they
require
a
significant
investment
in
training
samples,
contradicting
motivation
of
reducing
cost
acquiring
field.
The
combination
feature
extraction
and
regression
also
achieve
high-precision
fields,
which
is
more
suitable
tackle
three-dimensional
small
dataset.
In
this
study,
we
propose
reduced-order
model
(ROM)
for
utilizing
proper
orthogonal
decomposition
extract
representative
features
Gaussian
process
improved
automatic
kernel
construction
(AKC-GPR)
perform
nonlinear
mapping
physical
prediction.
selection
variables
based
on
sensitivity
analysis
modal
assurance
criterion.
underlying
relationship
unveiled
between
inflow
conditions.
ROM
exhibits
high
predictive
accuracy,
mean
absolute
percentage
error
(MAPE)
total
less
than
3.5%,
when
varying
altitudes
Mach
numbers.
During
angle
attack
variations,
only
effectively
reconstructs
distribution
by
interpolation
MAPE
7.02%.
excellent
small-sample
fitting
capability
our
AKC-GPR
algorithm
demonstrated
comparing
original
AKC-GPRs
maximum
reduction
35.28%.
These
promising
findings
suggest
that
proposed
serve
as
an
effective
approach
accurate
predicting,
enabling
its
application
analysis.
Physics of Fluids,
Journal Year:
2024,
Volume and Issue:
36(1)
Published: Jan. 1, 2024
Reducing
the
design
variable
space
is
crucial
in
multi-objective
airfoil
profile
optimization
to
improve
efficiency
and
reduce
computational
costs.
Based
on
random
forest
deep
neural
networks
(DNNs),
this
work
performs
range
reduction
ten
variables
obtained
through
a
fourth-order
class
shape
transformation
parameterization
method
for
subsonic
profiles.
Three
aerodynamic
performance
objectives
(lift
coefficient,
drag
lift-to-drag
ratio)
are
evaluated
using
Reynolds-averaged
Navier–Stokes
equations,
two
radar
stealth
(horizontal
vertical
polarization
cross
sections)
assessed
of
moments.
By
combining
DNN
architecture
with
an
improved
regression
prediction
capability,
predictive
models
trained
mapping
objectives.
The
errors
below
3%
1%
particle
swarm
algorithm
provides
optimized
profiles
three
scenarios.
First
higher
lift
coefficient
lower
section.
Second
Third
coefficient.
Increasing
curvature
reducing
maximum
thickness
improves
by
386
counts
reduces
17
counts.
curving
leading
edge,
section
transverse
electric
magnetic
polarizations
decreased
2.78
2.09
dBsm,
respectively.
Physics of Fluids,
Journal Year:
2024,
Volume and Issue:
36(1)
Published: Jan. 1, 2024
Transonic
flow
fields
are
marked
by
shock
waves
of
varying
strength
and
location
crucial
for
the
aerodynamic
design
optimization
high-speed
transport
aircraft.
While
deep
learning
methods
offer
potential
predicting
these
fields,
their
deterministic
outputs
often
lack
predictive
uncertainty.
Moreover,
accuracy,
especially
near
critical
regions,
needs
better
quantification.
In
this
paper,
we
introduce
a
domain-informed
probabilistic
(DIP)
framework
tailored
transonic
with
called
DIP-ShockNet.
This
methodology
utilizes
Monte
Carlo
dropout
to
estimate
uncertainty
enhances
flow-field
predictions
wall
region
employing
inverse
distance
function-based
input
representation
field.
The
obtained
results
benchmarked
against
signed
function
geometric
mask
representations.
proposed
further
improves
prediction
accuracy
in
wave
areas
using
loss
function.
To
quantify
our
predictions,
developed
metrics
assess
errors
location,
achieving
6.4%
1%,
respectively.
Assessing
generalizability
method,
tested
it
on
different
training
sample
sizes
compared
proper
orthogonal
decomposition
(POD)-based
reduced-order
model
(ROM).
Our
indicate
that
DIP-ShockNet
outperforms
POD-ROM
60%
complete
Physics of Fluids,
Journal Year:
2024,
Volume and Issue:
36(4)
Published: April 1, 2024
The
optimization
of
aerodynamic
components'
geometric
shapes
demands
a
novel
technical
approach
for
adaptive
and
efficient
exploration
decision-making
within
the
design
space.
In
this
study,
we
introduce
an
innovative
shape
framework
that
leverages
deep
reinforcement
learning
with
neural
network
surrogate
models.
field
prediction
surrogate,
realized
by
two
distinct
U-net
architectures,
can
efficiently
generate
holistic
solutions
based
on
transformed
mesh
coordinates.
Subsequently,
inference
engine
dynamically
calculates
key
metric
flow
fields,
serving
as
objective
function
subsequent
geometry-aware
Deep
Q
(DQN)-based
optimization.
framework's
efficacy
is
validated
using
rocket
nozzle
illustrative
example.
During
validation,
under
both
friction
frictionless
conditions,
l1
errors
entire
vision
transformer
(ViT)
convolutional
(CNN)
architectures
are
less
than
0.4%.
proposed
ViT
consistently
outperforms
CNN,
superiority
particularly
evident
in
complex
areas,
outlet
sections,
vacuum
thrust
prediction.
Following
training,
DQN
model
employed
to
explore
variable
B-spline
defining
profile
successfully
optimized
final
expanding
segment
improved
thrust.
Under
it
closely
approaches
theoretical
optimum.
practical
condition
considering
friction,
gains
2.96%
improvement.
results
demonstrate
framework,
especially
when
coupled
ViT,
exhibits
enhanced
accuracy
adaptability
tasks.
Physics of Fluids,
Journal Year:
2025,
Volume and Issue:
37(2)
Published: Feb. 1, 2025
Repeatedly
solving
flow
around
structures
with
varying
parameters
using
computational
fluid
dynamics
(CFD)
is
often
essential
for
structural
design.
This
study
proposes
a
boundary-assimilation
Fourier
neural
operator
(BAFNO)
method
to
address
the
challenges
of
manually
setting
initial
conditions
CFD.
The
focus
BAFNO
on
generalization
ability
predict
fields
without
relying
observational
data.
addresses
boundary
constraint
requirements
existing
physics-informed
models
in
parametric
geometries.
Inspired
by
ghost
node
method,
domain
are
assimilated
into
loss
function
instead
adding
penalty
terms.
Meanwhile,
structure
boundaries
damping
source
term
level
set
function.
can
flexibly
handle
geometries
different
shapes
and
quantities.
Subsequently,
series
numerical
experiments
flow-around
conducted
confirm
performance
BAFNO.
results
indicate
that
has
strong
capability,
+
CFD
obtain
dynamic
stable
faster
than
direct
Physics of Fluids,
Journal Year:
2025,
Volume and Issue:
37(3)
Published: March 1, 2025
The
fillet
on
the
submarine
is
a
rounded
structure
designed
based
body-stern
appendages,
which
effectively
weakens
horseshoe
vortex
at
junction
between
rudder
and
hull,
thereby
improving
propeller's
inflow
quality.
To
investigate
impact
of
stern
shape
wake
flow,
this
research
develops
data-driven
steady
field
prediction
model
for
submarines
U-Net
architecture.
By
comparing
computational
fluid
dynamics
(CFD)
simulation
results
with
model,
it
demonstrated
that
efficiency
flow
significantly
improved,
accuracy
can
be
maintained
simultaneously.
Furthermore,
effects
fillets
different
radii
are
analyzed
optimal
parameters
identified.
Compared
to
original
optimized
design
reduces
velocity
non-uniformity
by
20%.
Physics of Fluids,
Journal Year:
2025,
Volume and Issue:
37(3)
Published: March 1, 2025
This
paper
presents
a
nonlinear
reduced-order
modeling
(ROM)
framework
that
leverages
deep
learning
and
manifold
to
predict
compressible
flow
fields
with
complex
features,
including
shock
waves.
The
proposed
DeepManifold
(DM)-ROM
methodology
is
computationally
efficient,
avoids
pixelation
or
interpolation
of
field
data,
adaptable
various
grids
geometries.
consists
four
main
steps:
First,
convolutional
neural
network-based
parameterization
network
extracts
shape
modes
directly
from
aerodynamic
Next,
applied
reduce
the
dimensionality
high-fidelity
output
fields.
A
multilayer
perceptron-based
regression
then
trained
map
input
modes.
Finally,
back-mapping
process
reconstructs
full
predicted
low-dimensional
DM-ROM
rigorously
tested
on
transonic
RAE2822
airfoil
test
case,
which
includes
waves
varying
strengths
locations.
Metrics
are
introduced
quantify
model's
accuracy
in
predicting
wave
strength
location.
results
demonstrate
achieves
prediction
error
approximately
3.5%
significantly
outperforms
reference
ROM
techniques,
such
as
proper
orthogonal
decomposition
(POD)-ROM
isometric
mapping
(ISOMAP)-ROM,
for
training
sample
sizes.
Physics of Fluids,
Journal Year:
2025,
Volume and Issue:
37(3)
Published: March 1, 2025
Computational
fluid
dynamics
is
essential
for
airfoil
design
optimization.
Typically,
it
involves
numerous
numerical
procedures
such
as
grid
generation,
boundary
condition
setup,
and
simulations,
leading
to
high
computational
costs
extended
research
periods,
which
pose
a
long-standing
challenge
aerodynamic
development.
Recently,
the
data-driven
deep
learning
method
has
emerged
new
approach,
significantly
reducing
time.
However,
these
models
have
difficulties
maintaining
desired
accuracy,
particularly
when
balancing
surface
characteristics
with
internal
volume
features.
In
this
study,
we
introduce
novel
utilizing
multi-task
(MTL)
handle
predictions
interconnected
yet
distinct
tasks.
By
employing
multi-head
neural
network
architectures
advanced
MTL
optimization
strategies,
our
approach
effectively
resolves
inherent
conflicts
between
domain
predictions.
Our
demonstrates
significant
improvement
in
predictive
accuracy
of
both
flow
fields
force
coefficients.
Extensive
experiments
were
conducted
using
an
open-source
dataset
that
includes
field
data
various
shapes
under
different
flight
conditions.
The
results
indicate
MTL-based
surrogate
model
outperforms
existing
models,
providing
more
reliable
efficient
tools
practical
applications
engineering.