Passive flow control in the wake of bed-mounted cylinders: a review and new experimental insights
Frontiers in Mechanical Engineering,
Journal Year:
2025,
Volume and Issue:
11
Published: May 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.
Language: Английский
Energy harvesting from wake-induced vibration of flexible flapper behind a bluff body
Physics of Fluids,
Journal Year:
2024,
Volume and Issue:
36(11)
Published: Nov. 1, 2024
Piezoelectric
energy
harvesting
from
ambient
vibrations
offers
a
promising
small-scale
generation
strategy,
with
wake-induced
vibration
of
flexible
structures
being
an
ideal
candidate.
This
study
examines
bluff
body
followed
by
fully
piezoelectric
flapper
in
viscous
free-stream
flow
using
in-house
discrete
forcing
immersed
boundary
method-based
fluid-structure-electric
solver
for
parametric
investigation.
Different
vortex
shedding
regimes
are
identified
based
on
formation
around
the
flapper.
The
complex
and
interdependent
spatiotemporal
dynamics
wake
dictated
parameters
such
as
bending
rigidity
gap
space
between
result
various
deformation
profiles,
influencing
strain
rate
output
power.
also
investigates
independent
variation
length
its
impact
vortical
arrangements
flexibility,
introducing
different
oscillation
modes.
present
takes
nuanced
view
overall
their
mutual
effect
power
output,
unlike
most
existing
studies
where
enhancing
amplitude
frequency
oscillations
optimal
was
main
concern.
Factors
curvature,
asymmetry,
periodicity
have
been
especially
highlighted
context
corresponding
spaces
investigated.
Interestingly,
increase
piezo-flapper
has
seen
reduction
though
it
instrumental
bringing
symmetry
back.
comprehensive
insights
into
underlying
dynamical
mechanisms
can
contribute
toward
design
future
devices.
Language: Английский