Front propagation in laser-tweezed lipid bilayer tubules

1996 ◽  
Vol 463 ◽  
Author(s):  
Peter D. Olmsted ◽  
Fred C. Mackintosh
Keyword(s):  
Surface Tension ◽  
Boundary Conditions ◽  
Lipid Bilayer ◽  
Control Parameter ◽  
Laser Intensity ◽  
Front Propagation ◽  
Chemical Potentials ◽  
Unstable Medium ◽  
Lipid Tubules ◽  
Correct Boundary Conditions

AbstractWe study the mechanism of the ‘pearling’ instability seen recently in experiments on lipid tubules under a local applied laser intensity. We argue that the correct boundary conditions are fixed chemical potentials, or surface tensions Σ, at the laser spot and the reservoir in contact with the tubule. While most qualitative conclusions of previous studies remain the same, the ‘ramped’ control parameter (surface tension) implies several new features. We also explore some consequences of front propagation into a noisy unstable medium.

Simulation of a fluid phase lipid bilayer membrane: Incorporation of the surface tension into system boundary conditions

1995 ◽  
Vol 5 (1-3) ◽  
pp. 45-53
Author(s):  
S. -W. Chiu ◽  
M. Clark ◽  
V. Balaji ◽  
S. Subramaniam ◽  
H. L. Scott ◽  
...  
Keyword(s):  
Surface Tension ◽  
Boundary Conditions ◽  
Lipid Bilayer ◽  
Fluid Phase ◽  
Bilayer Membrane ◽  
Lipid Bilayer Membrane ◽  
System Boundary

A Systematic Asymptotic Expansion Procedure for Slender Ships

1964 ◽  
Vol 8 (03) ◽  
pp. 15-23 ◽  
Author(s):  
E. O. Tuck
Keyword(s):  
Asymptotic Expansion ◽  
Boundary Conditions ◽  
Arbitrary Shape ◽  
Careful Consideration ◽  
Wave Resistance ◽  
Expansion Procedure ◽  
Systematic Solution ◽  
The Individual ◽  
Correct Boundary Conditions

Inner and outer expansions are used to formulate a systematic solution to the problem of the steady translation of a slender ship of arbitrary shape. Careful consideration is givien to finding the correct boundary conditions to be satisfied by successive terms in the expansions, and certain of the individual terms are determined partly or completely as functions of hull shape. Some results are given concerning the second approximations to the potential and wave resistance.

Numerical Analysis of the Primary Breakup Under High-Altitude Relight Conditions Applying the Embedded DNS Approach to a Generic Prefilming Airblast Atomizer

2013 ◽  
Author(s):  
Benjamin Sauer ◽  
Nikolaos Spyrou ◽  
Amsini Sadiki ◽  
Johannes Janicka
Keyword(s):  
Surface Tension ◽  
Boundary Conditions ◽  
High Altitude ◽  
Ambient Pressure ◽  
Planar Geometry ◽  
Slight Variation ◽  
Strong Impact ◽  
Wall Film ◽  
Primary Breakup ◽  
Liquid Wall

The primary breakup under high-altitude relight conditions is investigated in this study where ambient pressure is as low as 0.4 bar and air, fuel and engine parts are as cold as 265 K. The primary breakup is crucial for the fuel atomization. As of today, the phenomena dictating the primary breakup are not fully understood. Direct Numerical Simulations (DNS) of liquid breakup under realistic conditions and geometries are hardly possible. The embedded DNS (eDNS) approach represents a reliable numerical tool to fill this gap. The concept consists of three steps: a geometry simplification, the generation of realistic boundary conditions for the DNS and the DNS of the breakup region. The realistic annular airblast atomizer geometry is simplified to a Y-shaped channel representing a planar geometry. Inside this domain the eDNS is located. The eDNS domain requires the generation of boundary conditions. A Large Eddy Simulation (LES) of the entire Y-shaped channel and a Reynolds-Averaged Navier-Stokes Simulation (RANS) of the liquid wall film are performed prior to the DNS. All parameters are stored transiently on all virtual DNS planes. These variables are then mapped to the DNS. Thus, high-quality boundary conditions are generated. The Volume-of-Fluid (VOF) method is used to solve for the two-phase flow. The results provide a qualitative insight into the primary breakup under realistic high-altitude relight conditions. Instantaneous snapshots in time illustrate the behavior of the liquid wall film along the prefilmer lip and illustrate the breakup process. It is seen that a slight variation of the surface tension force has a strong impact on the appearance of the primary breakup. Case 1 with the surface tension corresponding to kerosene at 293 K indicates large flow structures that are separated from the liquid sheet. By lowering the surface tension related to kerosene at 363 K, the breakup is dominated by numerous small structures and droplets. This study proves the applicability of the eDNS concept for investigating breakup processes as the transient nature of the phase interface behavior can be captured. At this time, the authors only present a qualitative insight which can be explained by the lack of quantitative data. The approach offers the potential of simulating realistic annular highly-swirled airblast atomizer geometries under realistic conditions.

Adhesion of lipid tubules in an assembly

1998 ◽  
Vol 9 (5) ◽  
pp. 485-506 ◽  
Author(s):  
RICCARDO ROSSO ◽  
EPIFIANO G. VIRGA
Keyword(s):  
Surface Tension ◽  
External Field ◽  
Equilibrium Problem ◽  
Biological Systems ◽  
Critical Value ◽  
Stability Diagram ◽  
Energy Functional ◽  
Highly Nonlinear ◽  
The Stability ◽  
Lipid Tubules

We study a unilateral equilibrium problem for the energy functional of a lipid tubule subject to an external field. These tubules, which constitute many biological systems, may form assemblies when they are brought in contact, and so made to adhere to one another along at interstices. The contact energy is taken to be proportional to the area of contact through a constant, which is called the adhesion potential. This competes against the external field in determining the stability of patterns with flat interstices. Though the equilibrium problem is highly nonlinear, we determine explicitly the stability diagram for the adhesion between tubules. We conclude that the higher the field, the lower the adhesion potential needed to make at interstices energetically favourable, though its critical value depends also on the surface tension of the interface between the tubules and the isotropic fluid around them.

Asymptotic model for the dynamics of curved viscous fibres with surface tension

2009 ◽  
Vol 622 ◽  
pp. 345-369 ◽  
Author(s):  
NICOLE MARHEINEKE ◽  
RAIMUND WEGENER
Keyword(s):  
Surface Tension ◽  
Boundary Conditions ◽  
Capillary Number ◽  
Temporal Evolution ◽  
Slender Body ◽  
Explicit Description ◽  
Asymptotic Model ◽  
Slender Body Theory ◽  
Viscous Transport ◽  
Body Theory

In this paper, we derive and investigate an asymptotic model for the dynamics of curved viscous inertial Newtonian fibres subjected to surface tension, as they occur in rotational spinning processes. Accordingly, we extend the slender body theory of Panda, Marheineke & Wegener (Math. Meth. Appl. Sci., vol. 31, 2008, p. 1153) by including surface tension and deducing boundary conditions for the free end of the fibre. The asymptotic model accounts for the inner viscous transport and places no restrictions on either the motion or the shape of the fibre centreline. Depending on the capillary number, the boundary conditions yield an explicit description for the temporal evolution of the fibre end. We study numerically the behaviour of the fibre as a function of the effects of viscosity, gravity, rotation and surface tension.

scholarly journals Front propagation in a vortex lattice: dependence on boundary conditions and vortex depth

Soft Matter ◽  
2016 ◽  
Vol 12 (43) ◽  
pp. 8935-8941 ◽  
Author(s):  
E. Beauvier ◽  
S. Bodea ◽  
A. Pocheau
Keyword(s):  
Boundary Conditions ◽  
Vortex Lattice ◽  
Front Propagation

Linear Spatial Evolution Formulation of Two-Dimensional Waves on Liquid Films Under Evaporating/Isothermal/Condensing Conditions

2002 ◽  
Author(s):  
Xuemin Ye ◽  
Chunxi Li ◽  
Weiping Yan
Keyword(s):  
Boundary Layer ◽  
Surface Tension ◽  
Reynolds Number ◽  
Evolution Equation ◽  
Film Thickness ◽  
Boundary Conditions ◽  
Liquid Films ◽  
Boundary Layer Theory ◽  
Spatial Evolution ◽  
Two Dimensional

The linear spatial evolution formulation of the two-dimensional waves of the evaporating or isothermal or condensing liquid films falling down an inclined wall is established for the film thickness with the collocation method based on the boundary layer theory and complete boundary conditions. The evolution equation indicates that there are two different modes of waves in spatial evolution. And the flow stability is highly dependent on the evaporation or condensation, thermocapillarity, surface tension, inclination angle and Reynolds number.

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