In
this
paper,
the
hydrodynamic
characteristics
of
a
hyperbolic
cylinder
under
periodic
pulsating
flow
are
studied.
The
non-uniform
turbulent
is
formed
by
periodically
oscillating
wing
structure
placed
upstream
cylinder.
influence
different
oscillation
velocities
and
amplitudes
horizontal
distance
between
on
downstream
studied,
results
indicate
that
mainly
determined
leading-edge
vortices
trailing-edge
vortex
shedding
itself.
Further,
has
an
obvious
owing
to
difference
in
diffusion
range
vortex.
Also,
lead
attachment
cylinder,
which
indicates
positive
or
negative
drag
coefficient.
Moreover,
critical
value
amplitude
exists
for
each
velocity
value,
so
subjected
minimum
force
incoming
flow.
Water,
Год журнала:
2025,
Номер
17(3), С. 292 - 292
Опубликована: Янв. 21, 2025
This
study
numerically
investigates
the
three-dimensional
flow
characteristics
around
circular
cylinders
of
finite-
and
infinite-lengths
under
subcritical
Reynolds
numbers
using
SST
κ–ω
turbulence
model
within
OpenFOAM.
The
simulations
were
conducted
for
aspect
ratios
(ARs)
2,
5,
10
(Re)
1
×
104,
3
5
105.
Under
infinite
conditions,
drag
coefficient
(Cd)
lift
(Cl)
exhibit
Cl
ear
transitions
from
steady
to
unsteady
regimes
as
Re
increases,
driven
by
organized
vortex
shedding.
For
finite
presence
a
free
end
significantly
alters
flow,
inducing
strong
effects
such
high-velocity
regions
near
surface
complex
structures.
Cd
trends
show
reduced
values
slower
convergence
compared
cases
due
interference.
Additionally,
density
fixed
boundary
intensifies
with
increasing
Re.
These
findings
provide
comparative
understanding
dynamics
in
cases,
offering
insights
into
design
offshore
Journal of Marine Science and Engineering,
Год журнала:
2024,
Номер
12(11), С. 1892 - 1892
Опубликована: Окт. 22, 2024
In
ocean
engineering,
interactions
between
currents
and
risers
lead
to
regular
vortex
shedding
on
both
sides
of
the
riser,
causing
structural
deformation.
When
frequency
approaches
natural
structure,
resonance
occurs,
significantly
increasing
This
phenomenon
is
a
critical
cause
riser
failure.
Therefore,
dynamic
response
flexible
vortex-induced
vibrations
(VIV)
crucial
for
their
safety.
paper
employs
finite-volume
method
integrate
over
control
volumes
solve
forces,
such
as
pressure
shear
stress,
surface
while
finite-element
discretizes
continuous
body
into
elements
nodes
displacements
stresses.
A
strongly
coupled
utilized
at
each
timestep
iteratively
transfer
load-displacement
data
fluid
fields,
updating
boundary
conditions
domain
achieve
bidirectional
fluid–structure
interaction
simulation
in
seawater
environment
risers.
The
study
finds
that
three-dimensional
exhibits
multi-frequency
vibration
phenomena
broadband
characteristics
under
high
flow
velocity
conditions.
As
increases,
vortex-shedding
mode
observed
transition
from
simple
two
single
(2S)
more
complex
pair
+
(P
S)
(2P)
modes.
addition,
stiffness
ends
enhanced
by
fixed
conditions,
coupling
triggers
these
regions.
At
higher
velocities,
effects
result
modes
stronger
responses
riser.
CFD letters,
Год журнала:
2023,
Номер
15(6), С. 154 - 175
Опубликована: Апрель 20, 2023
Three-dimensional
flow
features
of
the
slender
rectangular
prism
with
cross-section
height
(H)
to
streamwise
depth
(D)
ratio
or
side
(D/H
=
0.5)
were
investigated
numerically
using
Large-eddy
simulations
(LES)
turbulence
model
Reynolds
number
Re
22000.
Four
different
aspect
ratios
(L/H
2.5
–
10)
employed
in
this
research
study
effect
spanwise
variation
on
pattern
around
prism.
Moreover,
instability-induced
motion
was
modeled
predict
alteration
characteristics
stationary
vibrating
states
test
model.
The
global
quantities
such
as
drag
force,
pressure
coefficient,
and
Strouhal
frequency
are
presented,
which
suggests
that
structure
end
tip
plays
an
essential
role
dependency
variation.
velocity
vector
variations
at
positions
also
demonstrated.
a
small
2.5)
exhibited
Karman
vortex
suppression
prism's
vicinity,
vortices
region
shrank.
show
behaviors
from
Results in Physics,
Год журнала:
2023,
Номер
50, С. 106577 - 106577
Опубликована: Май 27, 2023
A
two-dimensional
momentum
exchange-based
immersed
boundary–lattice
Boltzmann
method
(IB-LBM)
is
used
to
scrutinize
the
influence
of
corner
radii
on
characteristics
laminar
flow
around
square-like
cylinders
arranged
in
an
equilateral-triangular
configuration,
with
each
cylinder
represented
by
300
discrete
elements.
Numerical
simulations
were
carried
out
Newtonian
viscous,
incompressible,
and
constant
properties,
simultaneously
changing
ratio
λ
from
0.0
(square)
1.0
(circular),
Reynolds
number
Re
40
160,
gap
δ
0.5
5.0.
The
wake
patterns,
force
coefficients,
Strouhal
St
calculated
discussed.
numerical
outcomes
demonstrate
that
ratio,
Re,
have
a
prominent
characteristics.
patterns
λ-Re
plane
can
be
divided
into
steady-state,
flip-flopping,
anti-phase,
in-phase
modes
for
=
3.0.
drag
Cd
lift
Cl
coefficients
exhibit
decreasing
trend
increasing
radius
except
Clc1;
as
increased,
all
three
ranging
0
gradually
approached
zero.
steady
state
pattern
significantly
lower
than
other
states,
relationship
between
complex
irregular;
increases,
show
positive
correlation.
Engineering Applications of Computational Fluid Mechanics,
Год журнала:
2022,
Номер
16(1), С. 2243 - 2269
Опубликована: Ноя. 21, 2022
Tidal
energy
is
one
of
the
world's
most
predicable
renewable
sources
and
therefore
holds
great
potential
to
be
a
valuable
building
block
for
decarbonisation
electricity
production.
This
paper
focuses
on
Venturi
shaped
duct
structure
(shroud)
accelerate
flow
speed
at
vertical
axis
tidal
turbine
utilising
low
static
pressure
created
exit
shroud.
concept
known
as
Davidson
Hill
(DHV)
turbine.
By
constructing
nozzle
diffusor
using
hydrofoils,
initial
demonstrations
indicate
increased
system
efficiency.
However,
owing
number
geometric
structural
hydrofoil
variations,
only
general
description
location
hydrofoils
provided
in
order
facilitate
modelling
while
allowing
future
variations
devised.
The
conducted
investigations
focus
influence
sections
main
geometry
identifying
length
component
orthogonal
direction
dominant
parameter.
multiple
combinations
these
variables
it
clear
that
higher
fluid
velocities
result
larger
forces
which
must
supported
by
devices
structure.
Small
adjustments
reference
geometries
placement
spacing
improvements
flow.
Thus,
taking
slight
alteration
this
papers
outcome,
further
3D-simulation
study,
including
interaction
rotation,
completed
fully
characterise
systems
benefits.
insights
gained
from
work
will
allow
reduction
computational
costs
detailed
optimisation
study
into
adaption
wide
range
(environmental)
boundary
conditions.
Jurnal Rekayasa Mesin,
Год журнала:
2023,
Номер
13(3), С. 911 - 919
Опубликована: Янв. 3, 2023
Mechanical
vibration
is
a
potential
source
of
micro-electrical
energy
harvesting
mechanisms
for
micro
electrical
power
supply
IoT
system
networks,
wireless
and
sensors
where
the
requirements
are
relatively
lower
available
independently.
In
this
study,
characteristics
cylinder
response
as
trigger
from
flow-induced
vibrations
at
various
air
velocities
were
investigated
experimentally
in
wind
tunnel
test
section.
Harvesting
cylinder’s
motion
by
using
galfenol
(Fe-Ga)
material
was
also
simultaneously.
The
maximum
obtained
plain
model.
Cylinder
taper
variation
reduce
response.
position
major
(D)
minor
(d)
(or
inverse
position)
diameters
affects
However,
tapering
reduces
onset
with
respect
to
flow
velocity.
frequency
vortex
(Strouhal,
St)
ranges
0.25
0.12.
diameter
tapered
has
effect
on
decreasing
tends
be
stationary.
Minor
reduction
structure.
generated
model
about
8.5
mW
RMS
value
2.3
coefficient
4%.
