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Displaying 1 - 25 of 37

Equilibrium and stability of axisymmetric drops on a conical substrate under gravity

October 4, 2015
Author(s)
Asha K. Nurse, Sean A. Colbert-Kelly, Sam R. Coriell, Geoffrey B. McFadden
Motivated by recent investigations of toroidal tissue clusters that are observed to climb conical obstacles after self-assembly, we study a related problem of the determination of the equilibrium and stability of axisymmetric drops on a conical substrate

On the Stability of Rotating Drops

April 20, 2015
Author(s)
Asha K. Nurse, Sam R. Coriell, Geoffrey B. McFadden
We consider the equilibrium and stability of rotating axisymmetric fluid drops by appealing to a variational principle that characterizes the equilibria as stationary states of a functional containing surface energy and rotational energy contributions

Morphological Stability

December 5, 2014
Author(s)
Robert F. Sekerka, Sam R. Coriell, Geoffrey B. McFadden
The theory of morphological stability provides a dynamical analysis of the stability of the interface that separates phases during a phase transformation. We focus on crystallization from either a pure or alloy melt. One solves the governing equations for

Bubble motion and size variation during thermal migration with phase change

January 1, 2013
Author(s)
Asha K. Nurse, Geoffrey B. McFadden, Sam R. Coriell
An analysis of the motion of a spherical bubble in a two-phase, single component system with a vertical linear temperature gradient is presented. The model for the migration of an immiscible bubble under the effects of buoyancy and thermocapillarity

Onset of Morphological Instability in Two Binary Liquid Layers

April 1, 2011
Author(s)
Geoffrey B. McFadden, Sam R. Coriell, Aaron Lott
We consider the linear stability of a horizontal fluid bilayer subject to vertical heating. The two layers consist of a binary fluid that has undergone a phase transition, resulting in a horizontal interphase boundary between two phases with different

Onset of Convection in Binary Liquid Layers

March 24, 2010
Author(s)
Geoffrey B. McFadden, Sam R. Coriell, Aaron Lott
We perform linear stability calculations for horizontal bilayers of a two-component fluid that can undergo a phase transformation, taking into account both buoyancy effects and thermocapillary effects in the presence of a vertical temperature gradient

The Solidification of an Ideal Ternary Alloy in a Mushy Layer

March 24, 2010
Author(s)
Daniel M. Anderson, Geoffrey B. McFadden, Sam R. Coriell, Bruce Murray
We consider a model for the solidification of an ideal ternary alloy in a mushy layer that incorporates the effects thermal and solutal diffusion, convection and solidification. Our results reveal that although the temperature and solute fields are

Onset of Oscillatory Convection in Two Liquid Layers with Phase Change

March 2, 2009
Author(s)
Geoffrey B. McFadden, Sam R. Coriell
We perform linear stability calculations for horizontal fluid bilayers that can undergo a phase transformation in the presence of a vertical temperature gradient. We reconsider the oscillatory instability calculated by Huang and Joseph [J. Fluid Mech. 242

Convective Instabilities in Two Liquid Layers

January 1, 2007
Author(s)
Geoffrey B. McFadden, Sam R. Coriell, Katharine F. Gurski, David Cotrell
We perform linear stability calculations for horizontal fluid bilayers, taking into account both buoyancy effects and thermocapillary effects in the presence of a vertical temperature gradient. To help understand the mechanisms driving the instability we

Onset of Convection in Two Liquid Layers with Phase Change

January 1, 2007
Author(s)
Geoffrey B. McFadden, Sam R. Coriell, Katharine F. Gurski, David Cotrell
We perform linear stability calculations for horizontal fluid bilayers that can undergo a phase transformation, taking into account both buoyancy effects and thermocapillary effects. We compare the familiar case of the stability of two immiscible fluids in

Numerical Modeling of Diffusion-Induced Deformation

September 11, 2006
Author(s)
J A. Dantzig, William J. Boettinger, James A. Warren, Geoffrey B. McFadden, Sam R. Coriell, R F. Sekerka
We present a numerical approach to modeling the deformation induced the the Kirkendall effect in binary alloys. The governing equations for isothermal binary diffusion are formulated with respect to inert markers and also with respect to the volume

Lateral Deformation of Diffusion Couples

April 1, 2005
Author(s)
William J. Boettinger, Geoffrey B. McFadden, Sam R. Coriell, R F. Sekerka, James A. Warren
A model is proposed to describe the shape change (displacement field) of a binary diffusion couple when the intrinsic (lattice) diffusivities of the two substitutional atomic species differ. As for the Kirkendall effect, the displacement is due the

Influence of a Catalytic Surfactant on Roughness Evolution During Film Growth

July 24, 2003
Author(s)
Daniel Wheeler, Thomas P. Moffat, Geoffrey B. McFadden, Sam R. Coriell, Daniel Josell
celerator Coverage (CEAC) based mechanism for the impact of additives on the evolution of surface roughness is explained; the CEAC mechanism accounts for the conservation of locl coverage of adsorbed catalyst on a deforming interface. It has recently been

A Mechanism for Brightening: Linear Stability Analysis of the Curvature Enhanced Coverage Model

January 6, 2003
Author(s)
Geoffrey B. McFadden, Sam R. Coriell, Thomas P. Moffat, Daniel Josell, Daniel Wheeler, W Schwarzacher
This work presents experiments and theory describing a mechanism for how brighteners in electrolytes function. The mechanism involves change of local coverage of a deposition rate enhancing catalyst adsorbed on the surface through change of local surface

Convective and Morphological Instabilities During Crystal Growth

June 1, 2002
Author(s)
Geoffrey B. McFadden, Sam R. Coriell, B T. Murray
During crystal growth or solidification of a binary alloy from a liquid phase, temperature and solute gradients are inherently present and can give rise to fluid flow in the melt. The interaction of fluid flow with the crystal-meltinterface plays an

Applications of Morphological Stability Theory

April 1, 2002
Author(s)
Sam R. Coriell, Geoffrey B. McFadden
Recent applications of mormhological stability theory are reviewed. For growth of a binary alloy from the melt, the temperature-dependence of the solute diffusivity can have a significant effect on the critical wavelength at the onset of instability. The

Separation of Scales for Growth of an Alloy Needle Crystal

October 1, 2001
Author(s)
R F. Sekerka, Sam R. Coriell, Geoffrey B. McFadden
We reexamine the problem of a needle crystal (a model for a dendrite primary stalk) having the shape of a paraboloid of revolution growing at constant velocity from a supercooled binary alloy with given bulk concentration and far-field temperature. The

Effect of Flow Due to Density Change on Eutectic Growth

April 1, 2001
Author(s)
Sam R. Coriell, Geoffrey B. McFadden, William F. Mitchell, B T. Murray, J B. Andrews, Y B. Arikawa
The Jackson-Hunt model of eutectic growth is extended to allow for different densities of the phases. The density differences give rise to fluid flow which is calculated from a series solution of the fluid flow equations in the Stokes flow approximation

Alpha Case Thickness Modeling in Investment Castings

December 1, 2000
Author(s)
William J. Boettinger, Maureen E. Williams, Sam R. Coriell, Ursula R. Kattner, B A. Mueller
The alpha case thickness at the surface of a Ti-6Al-4V step wedge investment casting has been measured and successfully predicted. The prediction uses temperature-time results obtained from a heat flow simulation of the casting that was performed with a

Morphological Stability of a Binary Alloy: Temperature-Dependent Diffusivity

November 1, 2000
Author(s)
Sam R. Coriell, Geoffrey B. McFadden, S R. Vanaerenbergh
The effect of the temperature dependence of the diffusion coefficient on the morphological stability of a binary alloy during directional solidification is treated by a linear stability analysis. The Soret effect is also included in the analysis. Specific

The Effect of Oscillatory Shear Flow on Step Bunching

September 1, 2000
Author(s)
B T. Murray, Sam R. Coriell, A A. Chernov, Geoffrey B. McFadden
During crystal growth, an imposed shear flow at the crystal-fluid interface can impact the conditions for the onset of morphological instability. In previous work, we studied the effect of time-independent shear flows and anisotropic interface kinetics on

Effect of Surface Free Energy Anisotropy on Dendrite Tip Shape

July 1, 2000
Author(s)
Geoffrey B. McFadden, Sam R. Coriell, R F. Sekerka
In previous work, we found approximate solutions for paraboloids having perturbations with four-fold axial symmetry in order to model dendritic growth in cubic materials. These solutions provide self-consistent corrections through second order in a shape