Physics of Fluids,
Год журнала:
2024,
Номер
36(12)
Опубликована: Дек. 1, 2024
Revealing
the
interaction
between
an
air
bubble
and
a
cavitation
is
important
to
better
understand
mechanism
of
entrainment
mitigate
on
spillway
surfaces.
The
during
their
multi-periodic
evolution
investigated
based
compressible
three-phase
model,
considering
phase
transition
thermodynamic
effects.
results
indicate
that
has
evident
shielding
effect
bubble,
weakening
its
collapse
prolonging
oscillation
period.
Two
patterns
are
identified
according
whether
merging
two
bubbles
occurs
or
not.
inhibition
impact
stronger
in
pattern
1
relatively
moderate
2.
To
quantify
influence
dynamics,
radius,
pressure
load,
temperature
under
different
dimensionless
distances
(γ)
sizes
(ε)
analyzed.
As
γ
increases,
increase,
while
minimum
radius
decreases.
value
for
=
0.24
reduces
by
50.3%
compared
case
where
only
collapses.
In
addition,
decreases
with
increasing
ε.
21.6%
when
ε
increases
from
0.2
0.45.
These
findings
may
provide
some
new
references
understanding
macroscopic
interactions
cluster
cluster.
Journal of Fluids Engineering,
Год журнала:
2024,
Номер
147(5)
Опубликована: Окт. 29, 2024
Abstract
Cavitation
erosion
in
hydraulic
machinery
constitutes
a
multifaceted,
instantaneous
physicochemical
process
resulting
material
wear
and
decreased
efficiency.
This
paper
employs
an
enhanced
Eulerian–Lagrangian
method
to
evaluate
cavitation
erosion.
The
captures
erosive
impact
loads
released
by
the
nonspherical
collapse
of
near-wall
bubbles
integrates
them
with
one-dimensional
ductile
mode,
capability
lacking
traditional
homogeneous
mixture
methods.
A
classic
axisymmetric
nozzle
test
case
is
conducted
under
four
different
numbers
(σ
=
0.8,
0.9,
1.09,
1.6)
validate
reliability
new
approach.
Qualitative
quantitative
analysis
demonstrates
that
load
distribution
on
lower
upper
walls
aligns
experimental
measurements.
Compared
reference
works,
accurately
predicts
maximum
position
yields
narrower
area
closer
data.
Moreover,
relative
error
minimum
incubation
time
at
σ
0.9
wall
calculated
4.67%,
rate
36.6%.
pivotal
for
further
studying
how
various
materials
respond
wear.
Further
reveals
response
patterns
are
similar
conditions
1.09.
In
contrast,
surface
reduced
46.7%,
nearly
triples
1.6.
Ultrasonics Sonochemistry,
Год журнала:
2024,
Номер
109, С. 106999 - 106999
Опубликована: Июль 17, 2024
Hydrodynamic
cavitation
reactors
are
of
great
promise
for
the
applications
chemical
process
intensification
and
water
treatment.
In
this
work,
a
novel
cylindrical
rotational
hydrodynamic
reactor
(CRHCR)
with
rectangular
grooves
oblique
tooth
protrusions
on
rotor
surface
was
studied.
The
three-dimensional
characterization
within
CRHCR
observed
from
front
left
views
by
high-speed
camera
experiments.
Interestingly,
new
phenomenon
simultaneous
formation
attached
shear
found
in
CRHCR.
synergistic
effect
contributes
to
enhancement
performance
addition,
evolution
is
explored.
It
that
forms
trapezoidal-shaped
cloud
groove,
which
undergoes
three
various
stages:
incipient,
development,
collapse.
Finally,
pulsation
frequency
intensity
chamber
were
investigated.
results
show
same
at
speed
near
diverse
teeth.
As
increases,
increases
linearly.
These
findings
paper
benefit
understanding
mechanism
This
work
investigates
the
cavitation
and
fluid–structure
interaction
characteristics
of
a
flexible
NACA0015
hydrofoil.
The
simulation
incorporates
Zwart–Gerber–Belamri
model
two-way
interactions.
detached
eddy
method
is
employed
to
analyze
impact
elastic
deformation
on
hydrodynamic
performance.
vibrational
response
cavitating
flow
field
around
hydrofoil
are
investigated.
results
show
that
mode
shifts
with
increasing
speed.
Furthermore,
vertical
displacement
aligns
variations
in
volume
field.
structural
an
notably
affects
evolution
cavitation.
Additionally,
presence
influences
pattern
vortex
shedding
wakes
this
study
can
serve
as
reference
for
design
hydrofoils
constructed
from
composite
materials.
Engineering Applications of Computational Fluid Mechanics,
Год журнала:
2024,
Номер
19(1)
Опубликована: Дек. 30, 2024
Shape
optimization
of
airfoils
is
crucial
for
enhancing
the
aerodynamic
performance
large
blades.
Nowadays,
integration
computational
fluid
dynamics
and
intelligent
algorithm
has
become
dominant
approach
airfoil
shape
optimization.
However,
this
kind
method
still
faces
challenges
high-dimensional
design
space
high
cost
evaluation.
In
work,
a
novel
was
proposed
to
optimize
achieve
lift-drag
ratio.
The
integrates
convolutional
neural
networks
(CNNs),
physics-informed
(PINNs),
deep
reinforcement
learning
(DRL)
techniques.
CNNs
extract
image
features
from
compress
their
shapes
into
six
parameters.
This
significantly
reduces
number
fitting
parameters
provides
low-dimensional
space.
A
PINN-based
utilized
evaluate
performance,
addressing
issues
collapse
non-convergence
often
encountered
in
traditional
Xfoil
method.
Deep
employed
integrate
parameter
dimensionality
reduction
evaluation
methods,
identifying
optimal
solutions
facilitating
transferability.
results
demonstrate
an
enhanced
ratio
airfoils,
proximal
policy
(PPO)
strategy
improves
stability
algorithms.
A
cavitation
flow
can
greatly
impact
a
vehicle's
attitude
and
stability
when
exiting
water.
This
paper
adopts
an
improved
delayed
detached
eddy
turbulence
model
Schnerr–Sauer
as
well
the
volume-of-fluid
method
overlapping
grid
technique
to
investigate
this
effect.
In
addition,
experimental
system
of
underwater
launch
is
designed
built
independently,
which
numerical
results
are
in
good
agreement
with
results.
The
transient
structure
motion
characteristics
projectiles
successively
launched
studied.
When
axial
spacing
ranges
from
0
1.0
times
diameter
projectile,
both
severely
affected
various
extents
pattern,
vortex
structure,
characteristics.
It
worth
noting
that
internal
cavity
secondary
projectile
disturbed
by
wake
primary
resulting
large-scale
fractures
detachment
cavity,
but
its
good.
