Measuring scale-dependent shape anisotropy by coarse-graining: Application to inhomogeneous Rayleigh-Taylor turbulence
Physical Review Fluids,
Год журнала:
2023,
Номер
8(11)
Опубликована: Ноя. 7, 2023
A
novel
approach
is
introduced
to
measure
flow
anisotropy
at
all
length
scales.
It
valid
for
general
fields,
including
inhomogeneous
flows
with
complex
boundaries
where
traditional
Fourier
approaches
face
difficulties.
Application
two-
and
three-dimensional
Rayleigh-Taylor
turbulence
reveals
the
markedly
distinct
different
scales
due
differing
energy
cascade
directions.
Язык: Английский
Multi-scale dynamics of scalar transfer in Rayleigh–Taylor turbulent mixing
Journal of Fluid Mechanics,
Год журнала:
2025,
Номер
1011
Опубликована: Май 14, 2025
Miscible
Rayleigh–Taylor
(RT)
turbulence
exhibits
a
wide
range
of
length
scales
in
both
the
velocity
and
density
fields,
leading
to
complex
deformations
isoscalar
surfaces
enhanced
mixing
due
nonlinear
interactions
among
different
scales.
Through
high-resolution
numerical
simulations
coarse-graining
analysis,
we
demonstrate
that
variance
heavy
fluid
concentration,
initially
maximised
by
unstable
stratification,
progressively
cascades
from
larger
smaller
scales,
eventually
dissipates
at
smallest
scale.
The
transfer
scalar
variance,
$\Pi
^Y$
,
primarily
governed
filtered
strain
rate
tensor,
is
effectively
captured
model
links
surface
stretching.
On
other
hand,
backscatter
transfer,
represented
negative
component
influenced
vorticity
field.
Furthermore,
examine
directional
anisotropy
RT
turbulence,
enhancing
accuracy
separating
horizontal
mean
mass
fraction
its
fluctuating
part.
Язык: Английский
Study on the Behavior and State of Viscous Fractured Leakage Bridging and Plugging Slurry during the Pump-In and Pressurization Process
Processes,
Год журнала:
2024,
Номер
12(1), С. 203 - 203
Опубликована: Янв. 17, 2024
Clarifying
the
process
of
bridging
and
plugging
slurry
during
pumping
squeezing
can
effectively
improve
efficiency
accuracy
fractured
leakage
treatment
while
minimizing
impacts
on
safety
environment.
In
this
paper,
computational
fluid
dynamics
(CFD)
numerical
simulation
experimentation
(hydrostatic
settling
method)
are
combined
to
evaluate
dynamic
settlement
different
types
through
sedimentation
changes,
volume,
velocity
height
for
factors
such
as
viscosity,
particle
size,
density
concentration
slurry.
The
formula
is
obtain
following:
When
viscosity
more
than
30
mPa·s,
diameter
1.5
mm
(particle
size
half
fracture
width),
2.0–2.6
g/cm3;
it
shows
good
dispersion
performance
under
pressure
holding
after
lifting
bit.
results
show
that
should
not
exceed
two
times
density,
has
little
influence
volume.
Язык: Английский