Lattice Boltzmann simulation of low-speed fans with sound absorbers using impedance boundary condition
Journal of Sound and Vibration,
Год журнала:
2025,
Номер
unknown, С. 119066 - 119066
Опубликована: Март 1, 2025
Язык: Английский
Adjoint-based aeroacoustic shape optimization using lattice Boltzmann method for suppressing cavity tones at low Mach numbers
Journal of Sound and Vibration,
Год журнала:
2025,
Номер
unknown, С. 119131 - 119131
Опубликована: Апрель 1, 2025
Язык: Английский
Spacing effects on acoustic fields generated by flow past two circular cylinders in tandem and side-by-side arrangements
AIP Advances,
Год журнала:
2025,
Номер
15(5)
Опубликована: Май 1, 2025
The
acoustic
field
generated
around
two
cylinders
involves
complex
interactions
between
flow
and
sound,
it
remains
unclear.
Hence,
this
study
investigated
the
effects
of
cylinder
spacing
on
radiation
from
flows
past
identical
circular
arranged
in
tandem
side-by-side
configurations.
Direct
aeroacoustic
simulations
based
lattice
Boltzmann
method
were
conducted
at
a
Reynolds
number
150
for
two-dimensional
laminar
Mach
0.2.
analysis
focused
co-shedding
regime
configuration
parallel
vortex
street
configuration.
results
revealed
that
directivity
sound
by
was
primarily
governed
phase
difference
shedding
upstream
downstream
cylinders,
which
determined
longitudinal
regime.
Dipole-like
observed
when
in-phase,
whereas
quadrupole-like
anti-phase.
In
configuration,
transitioned
dipole
pattern
to
quadrupole
with
increasing
transverse
wavelength
scale
aeolian
tone.
When
equal
half
tonal
cross-flow
direction
strongest,
exhibiting
typical
dipole-like
directivity.
contrast,
one
full
wavelength,
weakest,
cloverleaf-like
(quadrupole-like)
pattern.
Язык: Английский
Passive flow control in the wake of bed-mounted cylinders: a review and new experimental insights
Frontiers in Mechanical Engineering,
Год журнала:
2025,
Номер
11
Опубликована: Май 21, 2025
Controlling
wake
flow
behind
bed-mounted
circular
cylinders
is
required
in
many
engineering
applications.
This
study
investigates
several
passive
control
mechanisms,
including
the
use
of
helical
strakes,
meshes,
foam
coverings,
slots,
and
holes.
A
detailed
review
existing
experimental
numerical
studies
conducted
to
examine
principles,
applications,
effects
each
method.
While
extensive
research
exists
on
individual
techniques,
comparative
between
different
methods
are
notably
lacking.
Additionally,
variations
approach
conditions
across
highlight
need
for
a
systematic
evaluation
under
identical
or
near-identical
inflow
conditions.
To
address
these
gaps,
particle
image
velocimetry
measurements
were
employed
capture
compare
unsteady
dynamics
various
types
cylinders.
Experiments
at
Reynolds
number
1.45×104
,
based
cylinder
diameter.
The
results
show
that
plain
cylinder’s
dominated
by
large
recirculation
region
downstream
bifurcation,
while
meshed
shows
minimal
deviation
from
characteristics.
with
holes
generate
localized
turbulence
spiraling
patterns,
diminishing
downstream.
strakes
induce
unique
channelized
sustained
downstream,
whereas
single
cross-slotted
enhance
near-wake
velocity
via
high-velocity
jets,
particularly
configuration,
making
it
ideal
heat
transfer
In
contrast,
foam-covered
effectively
reduce
fluctuations,
offering
potential
applications
requiring
stability
drag
reduction.
Язык: Английский
Neck shape optimization of resonator-type sound absorbers using adjoint lattice Boltzmann method
AIP Advances,
Год журнала:
2025,
Номер
15(6)
Опубликована: Июнь 1, 2025
Resonant
sound-absorbing
devices,
such
as
Helmholtz
resonators,
can
effectively
reduce
discrete
frequency
noise
radiated
from
various
engineering
equipment.
In
this
study,
we
attempted
to
improve
the
sound
absorption
characteristics
of
a
resonator
using
an
unsteady
adjoint
method
based
on
lattice
Boltzmann
equation.
The
adjoint-based
shape
optimization
created
concave
upper
side
and
convex
lower
neck,
alleviating
greater
extent
compared
with
straight
serrated
neck
shapes.
Furthermore,
fluid
simulation
results
revealed
that
process
did
not
alter
resonant
frequency.
A
visualization
energy
dissipation
function
indicated
presence
region
in
optimized
helped
increase
local
velocity
gradient
region,
thereby
enhancing
viscous
improving
performance.
was
suggested
play
role
preserving
by
compensating
for
creation
aligning
natural
source.
Our
findings
aid
design
devices.
Язык: Английский
Acoustic wave propagation in depth-evolving sound-speed field using the lattice Boltzmann method
Physics of Fluids,
Год журнала:
2024,
Номер
36(9)
Опубликована: Сен. 1, 2024
This
study
investigates
the
propagation
of
sound
waves
within
deep-sea
low-sound-speed
channels
using
lattice
Boltzmann
method,
with
a
key
focus
on
influence
depth-dependent
speed
wave
propagation.
The
depth-variable
condition
is
realized
through
incorporation
an
external
force
proportional
to
density
gradient.
After
model
verification,
investigations
into
two-dimensional
spreading
sources
reveal
that
curves
When
source
depths
differing
from
channel,
paths
deviate
due
contrasting
speeds
above
and
below.
situated
exhibit
converging
patterns.
simulations
also
detail
total
reflection
behavior
waves.
incident
angle
falls
exceeds
critical
angle,
remain
intact
thereby
enabling
preservation
high
amplitude
acoustic
signals
even
at
remote
locations.
subsequent
around
obstacles
demonstrate
channel
exhibits
better
signal
transmission
capabilities
in
presence
obstacles.
In
uniform
environment,
submarine
symmetric
pattern.
By
contrast,
under
depth-evolving
conditions,
submarines
operating
various
manifest
distinct
characteristics,
such
as
asymmetric
during
shallow
diving,
well
attenuation
or
silencing
when
cruising
channels.
These
findings
underscore
profound
implications
underwater
detection
transmission.
Язык: Английский
Numerical study on the flow and noise control mechanisms of a forced rotating cylinder
Journal of Sound and Vibration,
Год журнала:
2024,
Номер
unknown, С. 118772 - 118772
Опубликована: Окт. 1, 2024
Язык: Английский
On the influence of porous coating on vibration response and noise reduction of cylinders at high Reynolds numbers
Physics of Fluids,
Год журнала:
2024,
Номер
36(7)
Опубликована: Июль 1, 2024
In
the
present
study,
flow
simulation
based
on
a
two-dimensional
finite
volume
method
is
coupled
with
Ffowcs
Williams–Hawkings
acoustic
analogy
to
investigate
noise
around
vibrating
circular
cylinder
coated
different
models
of
porous
layers
over
range
Reynolds
numbers,
1700≤Re≤10
270.
The
incompressible,
and
properties
layer
are
constant
(Da=10,
ε=0.99).
mass
damping
ratios
m*=2.4
ξ=0,
respectively.
effects
vorticity
pressure
contours,
hydrodynamic
coefficients,
vibration
response,
sound
level
(SPL),
coefficients
(Cp)
an
elastically
mounted
examined
at
2≤Ur≤12.
According
results,
amplitude
decreases
by
more
than
60%
in
model
3
initial
branch
(2≤Ur≤6),
while
2
shows
maximum
reduction
90%
lower
(6≤Ur≤12).
Compared
bare
cylinder,
CD
max
50%
3.
best
CL
also
contributed
Ur<6
Ur>6.
Moreover,
highest
overall
for
all
numbers
up
6
dB
Re=6847.
Models
4,
5,
show
peak
values
SPL,
1
exhibit
minimum
numbers.
Therefore,
most
efficient
structural
design
suppression
vortex-induced
vibration.
Язык: Английский