The
Liutex
based
vortex
identification
method
is
superior
to
previous
methods
in
that
it
overcomes
the
issues
of
threshold
problem,
shear
contamination,
etc.,
with
a
clear
physical
meaning
direction
vector
represents
local
axis
rotation,
while
magnitude
equal
twice
angular
velocity
rigid-rotation
part
flow.
current
study
focuses
on
interaction
between
represented
rotation
and
residual
during
development
Λ
hairpin
boundary
layer
transition.
temporal–spatial
evolution
typical
vortical
structures
are
analyzed
Liutex–shear
decomposition
particular
attention
paid
position
strength
changes
shear.
Vortex
core
lines
extracted
investigate
mutual
interactions
inside
vortices.
It
demonstrated
for
vortex,
spanwise
rotating
motions
formed
at
head
region
can
persist
long
time
under
influence
surrounding
shear,
tail
stretches
down
near
wall
but
then
becomes
weaker
due
dissipation.
High-shear
regions
tend
be
located
top
or
below
When
legs
gets
stronger,
will
rolled
up
form
new
On
one
hand,
together
newly
consist
which,
turn,
leads
generation
second-
third-level
other
also
generates
many
smaller
streamwise
vortices
region.
results
show
very
important
Journal of Fluid Mechanics,
Год журнала:
2025,
Номер
1006
Опубликована: Март 4, 2025
The
turbulent
boundary
layer
is
a
region
where
both
preferential
dissipation
of
energy
and
the
production
significant
vorticity
arises
as
consequence
strong
velocity
gradients.
Previous
work
has
shown
that,
following
Reynolds
decomposition,
purely
fluctuating
component
enstrophy
dominant
term.
Near
wall
this
varies
in
complex
manner
with
height.
In
study,
we
additionally
decompose
strain
rate
terms
into
normal
non-normal
components
using
Schur
decomposition
are
able
to
explain
all
these
features
contributions
at
different
heights
from
constituents
involving
combinations
quantities.
What
surprising
about
our
results
while
mean
shear
action
larger-scale
structures
should
that
effects
over-riding
importance
wall,
most
important
individual
term
involves
transverse
direction.
part,
because
correlation
between
axis,
but
it
also
case
negative
mean.
Hence,
local
orthogonal
direction
plays
crucial
role
amplifying
yet
have
developed
component.
These
conclusions
support
emphasis
control
literature
on
wall.
Physical Review Fluids,
Год журнала:
2025,
Номер
10(5)
Опубликована: Май 15, 2025
Understanding
the
dynamics
of
turbulent
velocity
gradient
tensor
(VGT)
is
essential
to
gain
insights
into
Navier-Stokes
equations
and
improve
small-scale
turbulence
modeling.
However,
characterizing
VGT
conditional
on
all
its
relevant
invariants
in
a
continuous
fashion
extremely
difficult.
Hence,
this
paper,
we
represent
Lagrangian
using
network
where
each
node
represents
unique
flow
state
space
VGT.
The
sign
relative
magnitude
ranking
resulting
from
Schur
decomposition
determines
discrete
vector.
Our
analysis
reveals
intriguing
features
dynamics,
such
as
grouping
influential
nodes
eigenvalues
are
real,
proximity
right
Vieillefosse
tail.
We
relate
our
complex
approach
well-established
discretization
based
principal
invariants,
QR,
discriminant,
Δ
six
regions
representing
very
different
physical
topological
states.
study
shortest
paths
which
their
starting
ending
belong.
This
shows
that
typically
clockwise
path
Q−R
diagram
arises
varying
manner:
sometimes
region
transitions
multiple
pathways
more
equal
probability,
while
others
focused
specific
pivotal
these
interregion
dynamics.
Comparisons
an
enhanced
Gaussian
closure
model
show
captures
out-degree
distribution
for
well.
it
uses
greater
number
transition
real
far
less
efficient
at
generating
motions
counter
restricted
Euler
Published
by
American
Physical
Society
2025
