Physics of Fluids,
Journal Year:
2024,
Volume and Issue:
36(10)
Published: Oct. 1, 2024
Cavitation
is
a
transient,
highly
complex
phenomenon
found
in
numerous
applications
and
can
have
significant
impact
on
the
characteristics
as
well
performance
of
hydrofoils.
This
study
compares
evolution
transient
cavitating
flow
over
NACA4412(base)
(NACA
stands
for
National
Advisory
Committee
Aeronautics)
cambered
hydrofoil
same
modified
with
pimple
finite
(circular)
trailing
edge.
The
assessment
covers
sheet,
cloud,
supercavitation
regimes
at
an
8°
angle
attack
Reynolds
number
1×106,
cavitation
numbers
ranging
from
0.9
to
0.2.
aims
comprehensively
understand
role
rectangular
controlling
its
hydrodynamic
across
these
regimes.
Numerical
simulations
were
performed
using
realizable
model
Zwart–Gerber–Belamri
(ZGB)
resolve
turbulence
effects.
accuracy
present
numerical
predictions
has
been
verified
both
quantitatively
qualitatively
available
experimental
results.
analysis
includes
time
cavities,
temporal
variation
total
cavity
volume,
time-averaged
distributions
vapor
volume
fractions
along
chord
length,
their
parameters.
Results
demonstrate
that
pimples
impacts
different
In
sheet
regime
(σ=0.9),
NACA4412(pimpled)
exhibits
minimal
length
changes
compared
hydrofoil.
cloud
(σ=0.5),
initiation
occurs
differently,
starting
pimpled
location
hydrofoil,
unlike
just
downstream
nose
case
base
(σ=0.2),
remains
comparable,
but
larger
(σ=0.5
σ=0.2)
after
initial
fluctuations.
Furthermore,
shows
41%,
36%,
17%
lower
lift
coefficients,
46%,
27%,
9%
drag
coefficients
supercavitation,
respectively.
Physics of Fluids,
Journal Year:
2025,
Volume and Issue:
37(1)
Published: Jan. 1, 2025
To
reduce
the
adverse
damage
caused
by
cavitation
phenomena
to
hydraulic
machinery,
such
as
surface
erosion
of
equipment,
increased
mechanical
vibration,
and
decreased
service
life,
this
review
summarizes
from
aspects
instability
mechanisms,
prediction
methods,
suppression
methods.
In
terms
flow
two
main
mechanisms
that
affect
shedding
cloud
cavitation,
reentrant
jet,
bubbly
shock
wave,
were
thoroughly
summarized.
It
is
pointed
out
behavior
cavity
greatly
influenced
thickness
jet
relative
cavity,
wave
also
one
important
factors
in
vortex
dynamics.
a
detailed
comparison
analysis
made
between
traditional
methods
based
on
numerical
simulation
currently
popular
neural
networks.
The
former
mainly
includes
models
turbulence
models,
while
latter
application
chain
physics-informed
network,
pressure–velocity
long
short-term
memory,
other
networks
prediction.
artificial
intelligence
predictive
have
advantages
model
order
reduction
accurate
field
feature
parameters.
active
passive
Finally,
current
research
status
hydrofoil
article
discusses
looks
forward
direction
development.
Journal of Marine Science and Engineering,
Journal Year:
2024,
Volume and Issue:
12(8), P. 1277 - 1277
Published: July 29, 2024
This
study
investigates
cloud
cavitation
suppression
around
a
model-scale
NACA66
hydrofoil
using
active
water
injection
and
explores
the
effect
of
multiple
parameters.
Numerical
simulations
mixed-level
orthogonal
test
method
are
employed
to
systematically
analyze
impact
jet
angle
αjet,
location
Ljet,
velocity
Ujet
on
efficiency
energy
performance.
The
reveals
that
has
greatest
influence
suppression,
while
optimal
parameter
combination
(Ljet
=
0.30C,
αjet
+60
degrees,
3.25
m/s)
effectively
balances
performance
reducing
volume
by
49.34%
improving
lift–drag
ratio
8.55%.
found
jet’s
introduction
not
only
enhances
vapor
condensation
reduces
intensity
vapor–liquid
exchange
process
but
also
disrupts
internal
structure
clouds
elevates
pressure
suction
surface,
thereby
suppressing
cavitation.
Further
analysis
shows
positive-going
horizontal
components
enhance
ratio,
negative-going
have
detrimental
effect.
Jet
arrangements
near
trailing
edge
negatively
both
These
findings
provide
valuable
reference
for
selecting
parameters
achieve
balance
between
in
hydrodynamic
systems.
Physics of Fluids,
Journal Year:
2024,
Volume and Issue:
36(10)
Published: Oct. 1, 2024
Micro
vortex
generators
(mVGs)
control
cavitation
by
altering
the
boundary
layer
flow
structure.
This
study
employs
wall-adapting
local
eddy-viscosity
large
eddy
simulation
(WALE-LES)
turbulence
model
combined
with
Zwart–Gerber–Belamri
to
conduct
transient
numerical
simulations
on
National
Advisory
Committee
for
Aeronautics
0015
baseline
hydrofoil
and
equipped
mVGs
under
various
numbers.
The
proper
orthogonal
decomposition
method
experiments
verify
accuracy
consistency
of
these
regarding
cavity
scale.
elucidates
mechanisms
which
suppress
cloud
at
low
numbers
induce
high
Results
indicate
that
maintain
sheet
characteristics
numbers,
reducing
wall
pressure
fluctuations
enhancing
stability.
During
inception,
mVG-induced
leads
early
formation.
In
phase,
modal
energy
distribution
is
more
dispersed,
while
in
inception
concentrated
significant
dominant
modes.
Moreover,
counter-rotating
vortices
generated
mitigate
separation,
enhance
leading-edge
attachment
stability,
reduce
high-frequency
vibrations
caused
bubble
shedding.
significantly
advances
understanding
accurately
simulating
revealing
across
different
stages
using
WALE-LES
model.
findings
demonstrate
can
effectively
stabilize
structures
instabilities
overall
performance.
These
insights
will
have
a
impact
design
hydrofoils
development
strategies.
