Research Square (Research Square),
Journal Year:
2023,
Volume and Issue:
unknown
Published: Aug. 2, 2023
Abstract
Cavitation
commonly
induces
performance
deterioration
and
system
vibration
in
many
engineering
applications.
This
paper
aims
to
investigate
the
effects
of
air
injection
on
cavitation
evolution,
pressure
pulsation
a
centrifugal
pump
with
inducer.
In
this
paper,
high-speed
camera
is
used
capture
gas
flow
pattern
evolution
process
The
impacts
inlet
are
also
investigated.
results
show
that
development
inducer
undergoes
four
patterns:
incipient
cavitation,
sheet
cloud
super
cavitation.
As
becomes
more
severe,
main
frequency
shifts
lower
frequencies,
amplitude
increase.
addition,
promotes
but
delays
development.
A
small
amount
makes
cavity
shed
small-scale
clusters.
Meanwhile,
it
can
effectively
decrease
amplitudes
vibration.
content
increases,
fluctuations
Physics of Fluids,
Journal Year:
2023,
Volume and Issue:
35(10)
Published: Oct. 1, 2023
A
compressible
cavitation
model
is
developed
in
this
paper,
which
the
bubble
wall
velocity
obtained
by
solving
Rayleigh–Plesset
(R–P)
equation.
Additionally,
vapor
compressibility
also
included
during
evaporation/condensation
to
correct
phase
change
rate.
The
predicted
results
around
a
National
Advisory
Committee
for
Aeronautics
(NACA)
66
(mod)
hydrofoil
are
compared
with
available
experimental
data,
and
satisfied
agreement
obtained.
By
(mod),
we
mean
NACA
modified
Brockett
[“Minimum
pressure
envelopes
NACA-66
sections
=
0.8
camber
BuShips
type
I
II
sections,”
Technical
Report
No.
1780
(David
Taylor
Model
Basin
Washington
DC
Hydromechanics
Lab,
1966)]
Valentine
[“The
effect
of
nose
radius
on
cavitation-inception
characteristics
two-dimensional
hydrofoils,”
3813
(Naval
Ship
Research
Development
Center,
1974)].
Several
crucial
flow
properties,
e.g.,
fluid
compressibility,
evolution
features,
statistical
characteristics,
studied
detail.
suggest
that
better
suited
predicting
collapse
behavior
cavitation.
Moreover,
our
work
captures
liquid
re-entrant
jet
bubbly
shock
waves
well
reveals
these
two
mechanisms
jointly
dominate
cavity
shedding
dynamics.
Shock-induced
pulses
play
more
important
role
maximum
amplitude
exceeding
200
kPa,
significantly
larger
than
pulse
caused
jets.
Finally,
analysis
indicates
pulsating
presents
non-Gaussian
nature
positive
skewness,
exhibit
high-frequency
high-energy
characteristics.
Physics of Fluids,
Journal Year:
2023,
Volume and Issue:
35(7)
Published: July 1, 2023
Using
molecular
dynamics
simulation,
we
studied
thermodynamic
effects
of
a
nanobubble's
collapse-induced
erosion
occurring
at
different
ambient
temperatures.
We
analyzed
the
single
nanobubble
collapsing
near
an
aluminum
(Al)
solid
boundary
immersed
in
water
temperatures
ranging
10–60
°C
(283–333
K).
used
momentum
mirror
protocol
to
investigate
shock
wave
as
associated
nanojet
formed
and
moved
toward
boundary.
The
results
showed
that
was
during
collapse
process
after
collision
with
wave.
On
surface,
lower
greater
than
higher
Physics of Fluids,
Journal Year:
2023,
Volume and Issue:
35(2)
Published: Jan. 20, 2023
In
the
current
research,
we
studied
collapse
mechanism
of
nanobubble
under
mirror
and
real
wall
protocols
using
molecular
dynamics
simulation.
Moreover,
analyzed
reactive
properties
during
process.
Towards
this
aim,
an
aluminum
(Al)
slab
has
been
considered
as
a
wall,
its
behavior
after
formation
nanojet
investigated.
The
obtained
results
indicated
that
are
similar.
collision
between
shock
wave
leads
to
nanobubble,
was
formed
However,
can
sooner
when
Al
is
used
wall.
surface
roughness
propagation
increased
due
chemical
reaction
water
protocol,
while
roughness-free
from
beginning
end.
2Al
+
H2O→
AlOH
AlH
creates
amorphous
layer
containing
species
on
slab.
This
grows
semi-smoothly
bubble
shrinkage
process,
growth
type
changed
island
shape
complete
collapsing.
behind
vortices
collapse.
Physics of Fluids,
Journal Year:
2024,
Volume and Issue:
36(5)
Published: May 1, 2024
We
experimentally
investigated
a
passive
cavitation
control
approach
to
partial
and
cloud
on
National
Advisory
Committee
for
Aeronautics
0015
hydrofoil.
For
this
approach,
we
implemented
two
different
kinds
of
mesoscale
bio-inspired
riblets,
known
as
scalloped
riblets
sawtooth
the
suction
side
hydrofoil
near
its
leading
edge.
studied
dynamics
with
without
using
high-speed
camera.
In
addition,
performed
hydro-acoustic
measurements
analyze
effects
induced
noise
in
wake
hydrofoils.
considered
flows
at
Reynolds
numbers
0.5
×
106
0.6
hydrofoils
angles
attack
8°
10°.
Results
revealed
that
shedding
surface
was
mitigated
significantly
due
reduction
re-entrant
jet
momentum.
Also,
influence
tip
vortex
reduced
modified
Furthermore,
large-scale
unmodified
located
mostly
lower
frequency
range
30
Hz,
which
similar
cavity
frequency.
The
small-scale
vortex-induced
concentrated
relative
higher
between
100
120
Hz.
study
achieved
by
low
domain
some
cases
manipulating
oscillation
mechanism
elimination
structure.
This
provided
new
insight
into
controlling
destructive
should
be
relevant
various
engineering
applications.
Fluids,
Journal Year:
2023,
Volume and Issue:
8(5), P. 154 - 154
Published: May 14, 2023
In
this
work,
we
performed
molecular
dynamics
simulations
to
study
the
of
a
shock
wave-induced
single
nanobubble
collapsing
near
one
flexible
and
two
rigid
boundaries.
The
boundary
consisted
polyethylene,
boundaries
were
made
aluminum
iron.
waves
impinging
on
inside
system
generated
using
momentum
mirror
approach.
For
relative
wall
distances,
studied
shock-induced
its
collapse
atomic
velocity
contours
surrounding
collapse-induced
damage
analyzed.
We
obtained
from
ten
nanobubbles.
Results
showed
that
distance
affected
nanobubble’s
A
nanojet
was
directed
surfaces
during
process.
From
point
view,
depth
iron,
for
γ
=
1.3
6.0,
0.47
0.63
nm,
respectively.
It
observed
extensive
occurred
only
polyethylene
boundary.
