[�5�]� �H�.� �N�o�g�u�c�h�i� �a�n�d� �G�.� �G�o�m�p�p�e�r�,� �P�N�A�S� �1�0�2�,� �1�4�1�5�9� �(�2�0�0�5�)�.��[�6�]� �J�.� �L�.� �M�c�W�h�i�r�t�e�r�,� �H�.� �N�o�g�u�c�h�i�,� �a�n�d� �G�.� �G�o�m�p�p�e�r�,� �P�N�A�S��1�0�6�,� �6�0�3�9� �(�2�0�0�9�)�.��[�7�]� �H�.� �N�o�g�u�c�h�i�,� �e�t� �a�l�. �E�P�L� �8�9�,� �2�8�0�0�2� �(�2�0�1�0�)�.
Simple shear flow [1-4]Fluid vesicles exhibit transitions of their shapes and dynamics modes.Elongational transitions (from discocyte, stomatotye, or buded shape to prolate )and shrinking transition (prolate to discocyte) are found.
Capillary flow [5-7]As flow velocity increases, shear-elastic vesicles transit from a non-axisymmetric discocyte to an axisymmetric parachute shape, while fluid vesiclestransit from a discocyte to a prolate ellipsoid.In dense suspensions, the hydrodynamic interacitions induce orderedalignmens: single-file parchute and two-file.
CONCLUSION
[1] H. Noguchi and G. Gompper, Phys. Rev. Lett. 93, 258102 (2004).[2] H. Noguchi and G. Gompper, Phys. Rev. E 72, 011901 (2005).[3] H. Noguchi and G. Gompper, Phys. Rev. Lett. 98, 128103 (2007).[4] H. Noguchi, J. Phys. Soc. Jpn. 78, 041007 (2009).
Dynamics of Red Blood Cells and Fluid Vesicle in flows
Red blood cells and lipid vesicles exhibit rich behaviors in flows. We have studied their dynamics using a particle-based hydrodynamic simulationmethod, multi-particle collision (MPC) dynamics. Several transitions of their shapes and dynamic modes are discovered. In simple shear flow, threetypes of dynamic modes, tank-treading, tumbling, swinging, occur. They are coupled with shape deformation. In capillary flow, shape transition to para-chute shape and alignments of cells are observed. These results show good agreement with experiments.
capillary flow
!
/kBT R0 /kBT2bending modulus shear modulus
Linear dependence of transition velocities vm.(a) fluid and shear-elastic vesicles at R0 /kBT=112.(b) shear-elastic vesicles at /kBT=10.
c2
v m 0
/Rca
pc
!v m
0 /R
cap
c
0
100
0 500 10000
100
200
0 20 40
shear-elasticvesicle
fluidvesicle
discocyteto parachute
parachuteto discocyte
(a) (b)
Hiroshi Noguchi1 and Gerhard Gompper21Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan2Institut für Festkörperforschung, Forschungszentrum Jülich, 52425, Jülich, Germany
"
t /!0
0.5
1
20 40time
asph
erec
ity
Lipid vesicle in simple shear flow
Stomatocyte to pro late
s m a l l s h e a r
l a r g e s h e a r
s t o m a t o c y t e
p r o l a t e
Red blood cel lsin glass capi l laryt s u k a d a e t a l .M i c r o v a s c . R e s . 6 1 , 2 3 1 ( 2 0 0 1 ) .
sp
-0.5
0
0.5
0 50 100
0
0.2
0.4
t/ !
#/$
%!=0.92.
shear jump
%!=3.68.
"sp
0
0.5
1
t/!
"#/$
-0.5
0
0.5
0 50 100
spprolate(rod-like)
discocyte(red-blood-cell shape)
tank-treadingprolate
tumblingbuddedvesicle
Prolate to d iscocyteDashed l ines: s impletheoret ica l model
Budded vesic le to pro late( tumbl ing) ( tank- t reading)
mean pressure gragient
mea
n di
stan
ce b
etw
een
cellsIsolated fluid vesicle
Vesicle with shear elasticity
slow flow fast flow
slow flow fast flow
Red blood cel lsin microvesselS k a l a k e t a l . S c i e n c e 1 6 4 , 7 1 7 ( 1 9 6 9 ) .
Slipper in zigzag alignment
Parachute in single file alignment
Discocyte in random order
Discocyte
Slipper
Parachute
Dense system (L.J. McWhirter)
0
2
4
6
0 100 200
mean flow rate vm!0/Rcap
pres
sure
dro
p pe
r ves
icle
&
P ves
/Rca
p/v m
'0
shear-elasticvesicle
prolate
discocyte
parachute
fluid vesicle
