Assessing the effective settling of mineral particles in the ocean with application to ocean-based carbon-dioxide removal
Environmental Research Letters,
Journal Year:
2024,
Volume and Issue:
19(2), P. 024035 - 024035
Published: Jan. 24, 2024
Abstract
Ocean
alkalinity
enhancement
(OAE),
a
potential
approach
for
atmospheric
carbon
dioxide
removal
(CDR),
can
involve
introducing
milled
mineral
particles
into
the
ocean
to
promote
uptake.
The
effectiveness
of
this
method
relies
on
remaining
in
mixed
layer
while
dissolution
takes
place,
which
depends
particle
settling
rates.
Conventionally,
rates
are
assessed
using
Stokes
velocity
stagnant
conditions.
However,
recent
numerical
modeling
reveals
that
dynamic,
stratified
environments,
sediment
vertical
transport
be
up
an
order
magnitude
faster
than
because
two
types
fluid
instabilities
take
place
at
base.
Here,
we
estimate
effective
velocities
presence
these
and
assess
implications
efficacy
particular
OAE
CDR.
new
rate
estimates
sufficiently
rapid
there
is
negligible
before
settle
out
layer.
This
result
independent
initial
size
range
sizes
considered
here.
Findings
underscore
importance
considering
dynamics
stratification
assessing
provide
valuable
insights
optimizing
applications
diverse
marine
settings.
Language: Английский
Influence of stratified shear instabilities on particle sedimentation in three-dimensional simulations with application to marine carbon dioxide removal
Physical Review Fluids,
Journal Year:
2025,
Volume and Issue:
10(1)
Published: Jan. 10, 2025
The
vertical
transport
of
sediment
in
marine
settings
can
be
influenced
by
a
settling-driven
convective
instability
and
velocity
shear.
We
conduct
three-dimensional
numerical
simulations
to
investigate
out
surface
mixed
layer
under
different
shear
strengths.
show
how
this
is
determined
competition
between
the
growth
(Rayleigh-Taylor)
stratified
instabilities,
provide
implications
for
carbon
dioxide
removal.
In
weak
scenarios
(characteristic
difference
ΔU<0.05m
s−1),
Rayleigh-Taylor
drives
enhanced
compared
Stokes
particle
settling;
weakly
sensitive
strength
shear,
with
slowest
effective
settling
absence
presence
strong
(ΔU>0.05m
instabilities
grow
rapidly
suppress
instability,
particles
significantly
reduced.
Furthermore,
an
increase
rate
mass
decrease.
these
estimates
relate
limited
potential
atmospheric
draw
down
via
approaches
that
rely
on
dissolution
ocean.
locked
icon
Physics
Subject
Headings
(PhySH)Carbon
sequestrationKelvin-Helmholtz
instabilityMixing
geophysical
flowsParticle-laden
flowsRayleigh-Taylor
Language: Английский
Application of the entropy model to estimate flow discharge and bed load transport in a large river
Physics of Fluids,
Journal Year:
2025,
Volume and Issue:
37(2)
Published: Feb. 1, 2025
The
amount
of
sediment
bed
load
being
carried
by
rivers
significantly
impacts
the
inherent
development
riverine
systems
in
terms
hydrodynamic
and
morphodynamic
changes.
In
this
direction,
acoustic
Doppler
current
profiler
velocity
literature
data
collected
at
Óbidos
station
Amazon
River
were
applied
to
investigate
bed-load
transport
using
Entropy
method.
First,
cross-sectional
distribution
was
estimated
with
that
model
for
two
scenarios
source
data:
(a)
all
surface
velocities
(b)
single
as
maximum
velocity.
latter
analysis
conducted
different
assumptions
distribution:
parabolic
elliptic.
error
percentage
estimation
mean
discharge
2.08%
based
on
considering
4.08%
12.5%
elliptic
scenarios,
respectively.
Next,
shear
Shields
mobility
parameter
calculated
scenarios.
Finally,
dimensionless
rate
a
range
particle
diameters.
Applying
equations
various
distributions,
results
from
entropy
method
agreed
experimental
literature.
Overall,
study
highlighted
potential
estimate
river
large
relying
only
Language: Английский
Collisions among elongated settling particles: The twofold role of turbulence
Physics of Fluids,
Journal Year:
2024,
Volume and Issue:
36(1)
Published: Jan. 1, 2024
We
study
the
collision
rates
of
settling
spheres
and
elongated
spheroids
in
homogeneous,
isotropic
turbulence
by
means
direct
numerical
simulations
aiming
to
understand
microscale-particle
encounters
oceans
lakes.
explore
a
range
aspect
ratios
sizes
relevant
dynamics
plankton
microplastics
water
environments.
The
results
presented
here
confirm
that
between
particles
quiescent
fluid
are
more
frequent
than
those
among
spherical
due
oblique
settling.
also
demonstrate
generally
enhances
collisions
as
compared
expected
for
random
distribution
same
fluid,
although
we
find
decrease
highest
density
moderate
(A=5).
increase
rate
is
found
quickly
with
ratio,
reach
minimum
approximately
equal
5,
then
slowly
again,
an
up
50%
largest
investigated.
This
non-monotonic
trend
explained
result
two
competing
effects:
surface
area
ratio
(beneficial
encounter
rates)
alignment
nearby
prolate
(reducing
probability
collision).
Turbulence
mixing
is,
therefore,
partially
balanced
rod
at
high
particle
ratios.
Language: Английский