Applied Sciences,
Journal Year:
2024,
Volume and Issue:
14(21), P. 9733 - 9733
Published: Oct. 24, 2024
A
new
autonomous
underwater
vehicle
(AUV)
has
high
maneuverability
near
the
bottom
and
a
direction
turnaround
ability,
called
helicopter
(AUH).
This
paper
numerically
investigates
hydrodynamic
performance
of
AUH.
Reynolds-Averaged
Navier–Stokes
(RANS)
equation,
computational
fluid
dynamics
(CFD)
technique,
is
applied
to
analyze
AUH’s
behavior.
Investigations
characteristics
become
more
obvious
with
service
speed
in
range
0.4–1.2
m/s.
For
same
velocity
condition,
resistance
AUH
increases,
irregular
eddy
at
rear
expands
changes
angles
attack
length/height
ratio.
Essential
design
including
pressure,
distribution,
streamlines
are
shown
analyzed.
These
insights
can
be
used
as
guideline
reduce
drag
force
optimize
profile
for
future
designs.
It
great
potential
improving
control
algorithms.
Processes,
Journal Year:
2022,
Volume and Issue:
11(1), P. 42 - 42
Published: Dec. 25, 2022
The
energy-conversion
stability
of
hydropower
is
critical
to
satisfy
the
growing
demand
for
electricity.
In
low-head
plants,
a
gravitational
surface
vortex
easily
generated,
which
causes
irregular
shock
vibrations
that
damage
turbine
performance
and
input-flow
stability.
complex
fluid
dynamic
problem
with
high
nonlinear
features.
Here,
we
thoroughly
investigate
its
essential
hydrodynamic
properties,
such
as
Ekman
layer
transport,
heat/mass
transfer,
pressure
pulsation,
vortex-induced
vibration,
note
some
significant
scientific
issues
well
future
research
directions
opportunities.
Our
findings
show
turbulent
analytical
solution
multi-scale
modeling
technology,
working
condition
across
scale
transfer
mechanism,
high-precision
measurement
technology
high-speed
vortexes,
gas–liquid–solid
three-phase
dynamics
model
are
main
directions.
vibration
transition
mechanism
particle
flow
in
restricted
pipelines,
improvement
signal
processing
algorithms
better
design
anti-spin/vortex
elimination
devices,
continue
draw
attention.
relevant
result
can
offer
helpful
reference
fluid-induced
detection
provide
technical
energy
conversion.
Processes,
Journal Year:
2024,
Volume and Issue:
12(5), P. 884 - 884
Published: April 27, 2024
Micro-pits
are
widely
used
in
the
aerospace
and
tribology
sectors
on
cylindrical
surfaces
electrochemical
micromachining
which
of
great
significance
for
high
material
removal
rate,
absence
tool
wear,
mechanical
stress,
while
facing
significant
challenges
such
as
stray
corrosion
low
machining
efficiency.
Aiming
at
above
problems,
this
paper
proposes
a
comprehensive
method
called
radial
ultrasonic
rolling
(RUREMM)
an
field
has
been
added
onto
surface.
First,
theoretical
model
was
created
to
gain
rules
formation
collapse
bubbles
liquid
medium.
Second,
analyze
optimal
size
cathode
electrode,
COMSOL5.2
simulation
software
proposed
research
influence
electric
different
dimensions,
influences
parameters
RUREMM
depth/diameter
ratio
roughness
explored
through
processing
experiments.
Research
results
found
that
cavitation
bubble
undergoes
expansion,
compression,
oscillation,
where
max
deviation
is
less
than
12.5%.
The
optimized
chosen
200
×
μm2
electrode
spacing
800
μm
series
analyses.
Relevant
experiments
show
minimum
pits
with
width
212.4
μm,
depth
21.8
surface
(Ra)
0.253
were
formed
due
parameters.
can
offer
references
fabricating
micro-pits
enhanced
quality
precision
surfaces.
Journal of Marine Science and Engineering,
Journal Year:
2024,
Volume and Issue:
12(6), P. 921 - 921
Published: May 30, 2024
Cylindrical
shell
structures
have
excellent
structural
properties
and
load-bearing
capacities
in
fields
such
as
aerospace,
marine
engineering,
nuclear
power.
However,
under
high-pressure
conditions,
cylindrical
shells
are
prone
to
cracking
due
impact,
corrosion,
fatigue,
leading
a
reduction
strength
or
failure.
This
paper
proposes
static
modeling
method
for
damaged
liquid-filled
based
on
the
extended
finite
element
(XFEM).
It
investigated
impact
of
different
initial
crack
angles
propagation
path
failure
process
shells,
overcoming
difficulties
accurately
simulating
stress
concentration
at
tips
discontinuities
encountered
traditional
methods.
Additionally,
fluid-structure
interaction
theory,
dynamic
model
was
established,
analyzing
changes
pressure
flow
state
fluid
during
propagation.
Experimental
results
showed
that
although
angle
had
slight
effect
path,
ultimately
along
both
sides
main
axis
shell.
When
0°,
more
likely
form
through-crack,
with
highest
penetration
rate,
whereas
when
75°,
speed
slower.
After
entered
shell,
it
spurted
forming
wave
crest
ejection
position.
Energies,
Journal Year:
2025,
Volume and Issue:
18(2), P. 349 - 349
Published: Jan. 15, 2025
In
order
to
explore
the
influence
of
pilot
structure
on
lean
ignition
characteristics
in
a
certain
type
internally
staged
combustor,
current
study
was
conducted
effects
auxiliary
fuel
nozzle
diameter,
rotating
direction
swirler,
and
swirl
number
fuel–gas
ratio
limit,
combining
numerical
simulation
experimental
validation.
The
optimization
potential
mixing
this
combustor
further
explored.
It
indicated
that
limit
significantly
influenced
by
diameter
nozzles
swirler
combination
same
for
both
swirlers,
while
mass
flow
rate
air
constant.
Increasing
path
(0.4~0.6
mm)
having
excessively
higher
or
lower
numbers
module
primary
swirlers
are
not
conducive
broadening
boundary.
Compared
with
two-stage
rotation
combination,
performance
opposite
is
better.
Under
typical
working
conditions
(the
46.7
g/s
energy
4
J),
main
0.2
mm,
first-stage
1.4,
fuel–air
reduced
0.0121,
which
32.78%
than
baseline
scheme,
broadens
boundary
centrally
combustion
chamber.
Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Feb. 7, 2025
Shear
thickening
fluid
(STF)
has
unique
rheological
characteristics,
for
its
viscosity
is
dependent
on
the
variation
in
strain
rate
under
specific
shear
conditions.
STF
can
significantly
reduce
shocks
and
vibrations
by
absorbing
a
large
amount
of
impact
energy
during
external
loads.
The
dynamic
characteristics
STFs
high-frequency
loads
are
examined
this
work.
We
measured
changes
storage
modulus
dissipation
with
angular
frequency
performing
tests
STFs.
constructed
continuous
experiment
platform
It
possible
to
quantify
acceleration
force
at
varied
frequencies
platform.
Analysis
was
done
changing
law
STFs’
characteristics.
results
indicated
that
an
increase
fraction
leads
decrease
critical
frequency,
accompanied
pronounced
STF.
determined
as
0.255
rad/s
silica-polyethylene
glycol
(SiO
2
-PEG)
23%
0.349
cornstarch-water
60%.
Under
impact,
cornstarch
water
have
notable
effect,
while
SiO
-PEG
absorb
more
energy.
Sensors,
Journal Year:
2025,
Volume and Issue:
25(4), P. 1008 - 1008
Published: Feb. 8, 2025
In
the
process
of
unconventional
oil
and
gas
production,
a
large
number
microseismic
signals
are
generated.
These
received
by
geophones
deployed
on
ground
or
in
wells
used
for
safety
monitoring.
The
moving-coil
geophone
is
commonly
geophone,
which
widely
collecting
vibration
signals.
However,
current
conventional
have
certain
limitations
terms
frequency
band
range
cannot
fully
meet
low-frequency
requirements
We
studied
structure
material
properties
to
understand
factors
that
affect
their
band.
this
paper,
we
use
finite
element
analysis
method
perform
structural
10
Hz
combine
modal
excitation
response
obtain
its
operating
10.63–200.68
Hz.
then
discuss
effect
vibrating
components
range.
spring
sheet
mainly
natural
first-order
mode
(natural
frequency,
lower
limit
geophone),
lead
second-order
(spurious
upper
geophone).
By
analyzing
sensitivity
system
parts
selecting
more
suitable
sheets
materials,
higher
spurious
can
be
obtained,
thereby
achieving
purpose
broadening
expected
provide
help
actual
production.
Energies,
Journal Year:
2025,
Volume and Issue:
18(4), P. 984 - 984
Published: Feb. 18, 2025
This
article
aims
to
increase
the
intensity
of
mass
transfer
between
gas
and
liquid
in
counterflow
gas–liquid
flow,
one
key
problems
designing
equipment.
For
this
purpose,
analytical
experimental
studies
were
carried
out
evaluate
main
features
operating
processes
a
vortex
apparatus.
In
particular,
presented
research
substantiates
possibility
achieving
several
theoretical
stages
concentration
change
single
atomizing
stage
The
corresponding
stand
was
developed
carry
studies.
Afterward,
efficiency
apparatus
evaluated.
model
based
on
material
balance
flow
rate
equations,
allowing
for
determination
ratio.
After
comparing
expressions
with
results,
regression
dependence
evaluating
parameter
proposed
mathematical
obtained.
An
steam
consumption
led
increased
velocities,
affecting
droplets.
fact
proved
an
processes.
substantiated
achievement
From
practical
viewpoint,
confirmed
that
when
height
radius
ratio
is
less
than
0.6–0.7,
it
possible
create
plane
countercurrent
motion
flows
significant
peripheral
velocities
along
chamber.
