Hysteresis and bifurcations at spin up and spin down of a two-liquid vortex
Physics of Fluids,
Journal Year:
2025,
Volume and Issue:
37(5)
Published: May 1, 2025
Our
experiments
revealed
an
interesting
nonlinear
physics
phenomenon:
a
triple
hysteresis
and
few
bifurcations
in
compact
two-liquid
vortex
flow
driven
by
the
bottom
disk
rotation.
Two
immiscible
liquids
fill
vertical
cylindrical
container.
The
slow
rotation
drives
toroidal
axisymmetric
steady
circulations
of
both
liquids.
lower
liquid
moves
up
near
sidewall
down
axis,
eventually
forming
funnel
filled
with
upper
liquid.
If
angular
velocity
ωd
exceeds
first
critical
value
ω1,
then
pattern
loses
axial
symmetry
and,
particular,
horizontal
cross
section
from
circular
becomes
ellipsoidal.
second
ω2,
oscillatory
time.
third
ω3,
elliptical
splits
into
two
funnels
whose
axes
differ
axis
cylinder.
we
now
start
reducing
ωd,
reversed
order
passes
qualitatively
same
states,
but
smaller
values
ωd.
These
three
different
indicate
hysteresis.
A
hysteresis—the
dependence
state
on
prehistory—is
typical
feature
two-fluid
rotating
flows.
However,
discovered
here
is
new
striking
phenomenon.
Language: Английский
Magnetodielectric and Rheological Effects in Suspensions Based on Lard, Gelatin and Carbonyl Iron Microparticles
Published: July 2, 2024
This
study
aims
to
develop
low-cost,
eco-friendly
and
circular
economy-compliant
composite
materials
by
creating
three
types
of
magnetorheological
suspensions
(MRSs)
utilizing
lard,
carbonyl
iron
(CI)
microparticles,
varying
quantities
gelatin
particles
(GP).
These
MRSs
serve
as
dielectric
in
cylindrical
cells
used
fabricate
electric
capacitors.
The
equivalent
electrical
capacitance
(C)
these
capacitors
is
measured
under
different
magnetic
flux
densities
(B≤160
mT)
superimposed
on
a
medium-frequency
field
(f
=
1
kHz)
over
period
120
seconds.
results
indicate
that
at
high
values
B,
increasing
the
GP
content
20
vol.%
decreases
C
up
about
one
order
magnitude
compared
MRS
without
GP.
From
data,
average
Cm
are
derived,
enabling
calculation
relative
permittivities
(ϵr′)
dynamic
viscosities
(η)
MRSs.
It
demonstrated
ϵr′
η
can
be
adjusted
modifying
composition
fine-tuned
through
density
B.
A
theoretical
model
based
theory
dipolar
approximations
show
ϵr′,
magnetodielectric
effect
coarsely
finely
B
density.
ability
fine-tune
properties
highlights
versatility
materials,
making
them
suitable
for
applications
various
industries,
including
electronics,
automotive
aerospace.
Language: Английский
Magnetodielectric and Rheological Effects in Magnetorheological Suspensions Based on Lard, Gelatin and Carbonyl Iron Microparticles
Materials,
Journal Year:
2024,
Volume and Issue:
17(16), P. 3941 - 3941
Published: Aug. 8, 2024
This
study
aims
to
develop
low-cost,
eco-friendly,
and
circular
economy-compliant
composite
materials
by
creating
three
types
of
magnetorheological
suspensions
(MRSs)
utilizing
lard,
carbonyl
iron
(CI)
microparticles,
varying
quantities
gelatin
particles
(GP).
These
MRSs
serve
as
dielectric
in
cylindrical
cells
used
fabricate
electric
capacitors.
The
equivalent
electrical
capacitance
(C)
these
capacitors
is
measured
under
different
magnetic
flux
densities
(B≤160
mT)
superimposed
on
a
medium-frequency
field
(f
=
1
kHz)
over
period
120
s.
results
indicate
that
at
high
values
B,
increasing
the
GP
content
20
vol.%
decreases
C
up
about
one
order
magnitude
compared
MRS
without
GP.
From
data,
average
Cm
are
derived,
enabling
calculation
relative
permittivities
(ϵr')
dynamic
viscosities
(η)
MRSs.
It
demonstrated
ϵr'
η
can
be
adjusted
modifying
composition
fine-tuned
through
density
B.
A
theoretical
model
based
theory
dipolar
approximations
show
ϵr',
η,
magnetodielectric
effect
coarsely
finely
B
density.
ability
fine-tune
properties
highlights
versatility
materials,
making
them
suitable
for
applications
various
industries,
including
electronics,
automotive,
aerospace.
Language: Английский