A
large
amount
of
vegetation
in
nature
exists
the
form
heterogeneous
patches,
and
variations
characteristics
significantly
affect
water
flow
structures.
The
objective
this
study
is
to
investigate
effect
alternating
sparse
dense
patches
on
turbulence
characteristics.
Multiple
sets
scenarios
were
designed
for
numerical
simulation
analysis,
a
comparison
was
made
with
homogeneous
vegetation.
Results
indicate
that
compared
vegetation,
arrangement
alters
distribution
velocities
zone
main
channel,
promoting
material
exchange
between
these
regions.
density
difference
channel
increases
larger
differences,
but
magnitude
limited
generally
remains
within
10%
width.
In
balance
equation
turbulent
kinetic
energy,
terms
are
influenced
differently
by
changes
density.
As
increases,
convective
term
gradually
while
production
diffusion
exhibit
“lower
middle,
higher
at
both
ends”
pattern.
dissipation
demonstrates
reduction
low-density
ultimately
exhibits
an
amplification
effect.
Furthermore,
determines
using
data
from
mid-height
represent
entire
cross
section
may
result
maximum
error
up
11%.
Soil
erosion
on
the
slope
is
a
major
problem
in
northern
region
of
Pakistan,
causing
hill
instability
and
landslides.
Previous
research
focused
assessment
soil
hilly
regions
caused
by
intense
flooding.
However,
there
still
gap
investigating
impact
vegetation
patterns
densities
reduction
region.
Therefore,
current
fills
this
with
an
experimental
investigation
various
for
using
physical
model
regions.
Experiments
were
performed
under
diverse
scenarios
including
two
Froude
numbers
(Fr
=
0.17
0.20),
(G/d
2.13
1.09,
where
G:
between
elements,
d:
diameter
element),
three
slopes
(10°,
15°,
20°)
controlled
laboratory
setting.
The
findings
indicate
significant
contribution
denser
to
erosion.
Moreover,
newly
modified
pattern
was
introduced
modifying
existing
gaps
strips
followed
cutting
rate
9%
12%
compared
regular
arrangement
similar
scenarios.
Consequently,
outcomes
may
be
useful
establishing
bio-shields
as
environmentally
friendly
method
mitigating
Vegetation
plays
a
crucial
role
in
aquatic
systems
and
characterizes
riverine
ecosystems.
To
predict
changes
environment,
it
is
essential
to
understand
the
influences
of
vegetation
on
flow
structure
sediment
transport.
The
present
study
explores
effects
deflection
flexible
elements
vortex
deposition
around
patch
through
flume
experiments.
First,
velocity
measurement
by
particle
image
velocimetry
(PIV)
was
performed
for
flows
single
upright/inclined
rigid
strip
blade
single/three-row
inclined
blades
investigate
effect
structure.
Second,
flexibility
wake
region
were
explored
vertical
horizontal
PIV
measurements
In
this
part,
we
considered
three
types
models
consisting
rectangular
arranged
square
lattice
array:
(1)
rigid,
emergent
vegetation;
(2)
flexible,
submerged
(3)
vegetation.
case,
rotating
secondary
generated
significantly
contributes
momentum
transport
into
region,
while
turbulent
mixing
or
vortices
determines
behind
patches.
Moreover,
increases
spanwise
fluxes
across
lateral
edges
thereby
enhances
patch.
Proceedings of the Royal Society A Mathematical Physical and Engineering Sciences,
Год журнала:
2025,
Номер
481(2309)
Опубликована: Янв. 1, 2025
In
this
paper,
we
explore
the
formation
of
alternate
river
bars
in
presence
submerged
vegetation,
modelled
as
uniformly
spaced
rigid
cylinders.
We
analyse
stability
erodible
bed
by
coupling
Exner
equation
for
evolution
with
continuity
and
momentum
equations
fluid
phase.
Through
linear
weakly
nonlinear
analyses,
predict
equilibrium
wavelength
amplitude
vegetated
bars.
The
computational
results
hinge
on
two
key
parameters:
vegetation
aspect
ratio
(vegetation
height
to
diameter
ratio)
packing
density
(dimensionless
frontal
area
per
unit
volume).
present
streamwise
flow
velocity
profiles
different
ratios
densities.
find
that
decreases
higher
density.
Vegetation
reduces
minimum
channel
required
braided
threshold
bar
formation.
increases
but
density,
eventually
reaching
a
constant
value.
predicted
align
field
observations
Arc
River,
Hooge
Raam
Alpine
Rhine
River
Isère
River.
Water Resources Research,
Год журнала:
2022,
Номер
58(10)
Опубликована: Сен. 22, 2022
Abstract
Understanding
the
mechanisms
controlling
downstream
water‐level
variations
after
operation
of
Three
Gorges
Dam
is
important
for
riverine
flood
and
drought
management.
However,
our
quantitative
understanding
multiple
controls
river
morphology,
vegetation,
floodplain
resistance
on
water
levels
in
Middle
Yangtze
River
(MYR)
remains
limited.
Here,
we
analyze
changes
channels
MYR
using
450
cross‐sectional
profiles
as
well
data
discharge,
levels,
sediment,
satellite
images
from
2003
to
2015.
Results
show
an
overall
decline
low‐flow
water‐levels
(at
a
given
small
discharge)
due
severe
incisions
caused
by
sharp
reduction
∼90%
sediment
loads
1950–2002
2003–2020.
In
contrast,
high‐flow
large
display
minor
changes.
Our
analysis
shows
that
notably
increased
vegetation
growth
likely
dominant
factor
elevating
water‐levels,
followed
riverbed
coarsening
greater
fluctuations
longitudinal
profiles.
findings
further
geomorphic
response
dam
their
impacts
have
implications
management
dammed
systems.
Water Resources Research,
Год журнала:
2022,
Номер
58(8)
Опубликована: Авг. 1, 2022
Abstract
Laboratory
experiments
examined
the
longitudinal
evolution
of
near‐bed
velocity,
turbulent
kinetic
energy
(TKE),
and
net
deposition
in
a
model
Phragmites
australis
canopy
occupying
1/3
channel
width.
The
canopies
were
constructed
from
P
.
with
real
morphology
solid
volume
fraction
between
0.003
0.018.
An
exponential
was
modified
to
predict
velocity
inside
canopy,
which
TKE
can
be
predicted.
By
combining
predicted
probability,
we
proposed
distribution
canopy.
TKE,
good
agreement
measurements.
Relative
an
upstream
reference,
within
enhanced
when
two
conditions
met:
in‐canopy,
smaller
than
critical
value
for
resuspension,
resuspension
took
place
bare
channel.
Above
vegetation
density
(defined
by
ϕ
c
),
spatially‐averaged
surpassed
that
adjacent
provides
way
estimate
always
diminished
over
some
flow
adjustment
distance,
L
d
(distance
leading
edge
fully
developed
flow).
When
length
greater
0.4
,
canopy‐averaged
relative
Finally,
same
length,
differences
plant
morphologies
did
not
have
strong
impact
on
in‐canopy
distribution.
