IntechOpen eBooks,
Год журнала:
2023,
Номер
unknown
Опубликована: Дек. 4, 2023
Vortex
definition
and
identification
are
extremely
important
for
the
study
of
fluid
dynamics
research.
Liutex
is
a
newly
proposed
concept
that
correctly
represents
vortex.
vector
whose
direction
local
rotation
axis
magnitude
twice
angular
speed.
To
identify
unique
structure
vortex,
method
known
as
Core
Line
has
been
developed,
which
displays
rotational
core
However,
original
manual
method,
not
practical
real
application,
an
automatic
algorithm
required
usage.
Xu
et
al.
by
selecting
best
line
from
group
candidate
lines,
progress.
In
this
chapter,
another
perspective
to
solve
problem,
new
introduced
based
on
forward
gradient
lines.
Since
lines
have
feature
they
advance
maximums,
route
will
still
result
in
line,
avoids
process
find
line.
This
achieved
some
success
Lambda
vortex
early
boundary
layer
transition.
As
the
key
control
equipment
for
transmission
of
fluid
medium,
butterfly
valves
are
widely
used
in
systems
media
energy,
chemical
industry,
metallurgy,
aerospace
engineering,
and
other
fields,
playing
an
important
role
stability
reliability
system
operation.
When
flow
cross
section
suddenly
changes,
pressure
rapidly
decreases
downstream,
leading
to
cavitation
valves.
Cavitation
causes
serious
erosion
damage
valve
core
pipeline
surface,
resulting
leakage
noise
problems
valves,
which
seriously
affects
regulation
performance
lifetime
In
this
study,
numerical
analyses
conducted
investigate
evolution
at
transient
a
plate
through
model.
Moreover,
effects
opening
degree
rotating
speed
on
volume
distribution,
rate
change,
growth–collapse
cavitation,
correlation
between
vortex
closing
processes
investigated.
Due
influence
hysteresis,
characteristic
parameters
exhibit
different
behaviors
steel research international,
Год журнала:
2025,
Номер
unknown
Опубликована: Фев. 3, 2025
The
submerged
entry
nozzle
(SEN)
is
a
critical
component
in
the
continuous
casting
process,
facilitating
transfer
of
molten
steel
from
tundish
to
mold.
internal
flow
dynamics
within
SEN
are
crucial
as
they
influence
several
key
aspects
casting,
such
mold
characteristics,
inclusion
transport,
susceptibility
clogging,
and
ultimate
quality
produced
steel.
In
this
study,
hydraulic
model
established,
particle
image
velocimetry
(PIV)
employed
measure
velocity
magnitudes
inside
nozzle.
Computational
fluid
simulations
conducted
using
Reynolds‐averaged
Navier–Stokes
large
eddy
simulation
(LES)
with
varying
mesh
sizes.
time‐averaged
magnitude
calculated
by
shear
stress
transport
medium
LES
finer
resolution
exhibits
good
agreement
PIV
measurements.
Vortices
predominantly
observed
near
bottom
close
proximity
wall.
Notably,
pair
counter‐rotating
vortices
identified
at
bottom.
Furthermore,
transient
fluctuations
effectively
captured
employing
resolutions.
The
main
focus
of
this
paper
is
to
discover
the
link
between
flame
macrostructure
and
thermoacoustic
instability
in
a
centrally
staged
swirl
burner.
In
practical
combustors,
flow
rate
pilot
stage
much
smaller
than
that
stage.
However,
modification
could
alter
while
maintaining
similar
total
rate.
Therefore,
was
examined
at
different
macrostructures
by
varying
equivalence
ratio
under
identical
inlet
conditions.
High-frequency
planar
laser
measurements
chemiluminescence
measurement
were
conducted
enhance
spatial
temporal
accuracy,
providing
more
comprehensive
understanding
instability.
Two
macrostructures,
S-type
I-type
flames,
identified
based
on
preheating
zone
distribution.
They
exhibit
distinct
instabilities,
with
flames
demonstrating
intense
flames.
results
indicate
variation
influences
coupling
heat
release
field.
Specifically,
greater
sensitivity
field
fluctuations,
resulting
complex
fluctuation
flame.
This
discrepancy
leads
variations
intensity,
as
well
changes
phase
acoustic
pressure,
which
turn
impact
Rayleigh
index.
Meanwhile,
significant
differences
exist
distribution
pattern
range
fluctuations
Journal of Fluids Engineering,
Год журнала:
2022,
Номер
145(1)
Опубликована: Сен. 13, 2022
Abstract
This
study
investigates
the
turbulent
flow
properties
experimentally
in
vicinity
of
two
side-by-side
circular
cylinders,
along
with
influence
third
cylinder
same
dimension
placed
upstream
and
successively
downstream
forming
an
equilateral
triangle.
Three-dimensional
stereoscopic
particle
image
velocimetry
(PIV)
was
employed
to
collect
instantaneous
velocity
data
around
arrangements.
The
highlights
prime
parameters
turbulence
such
as
mean
velocities,
Reynolds
stresses,
kinetic
energy
(TKE),
quadrant
analysis,
Q-criteria
for
vortices,
which
are
responsible
development
various
problems
scour-hole
cylindrical
pier
arrangements,
disturbance
industrial
marine
structures.
spectral
analysis
performed
examine
distributions,
vortex-shedding
frequencies
corresponding
Strouhal
numbers.
Dominant
vorticity
locations
were
identified
from
contours
Q-criteria.
magnitude
characteristics
reduced
by
15–20%
(turbulence
intensity
20%
TKE
15%)
when
group.
Streamlines
also
studied
visualize
patterns
a
better
understanding
physics
presence
cylinder.
maximum
vortices
obtained
spectrum
showed
that
generated
less
is
upstream.
