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Predicting Bite Force In Mammals: Two-Dimensional Versus Three-Dimensional Lever Models, Jl Davis, Se Santana, Er Dumont, Ir Grosse
Predicting Bite Force In Mammals: Two-Dimensional Versus Three-Dimensional Lever Models, Jl Davis, Se Santana, Er Dumont, Ir Grosse
Jeffrey M. Davis
Bite force is a measure of whole-organism performance that is often used to investigate the relationships between performance, morphology and fitness. When in vivo measurements of bite force are unavailable, researchers often turn to lever models to predict bite forces. This study demonstrates that bite force predictions based on two-dimensional (2-D) lever models can be improved by including three-dimensional (3-D) geometry and realistic physiological cross-sectional areas derived from dissections. Widely used, the 2-D method does a reasonable job of predicting bite force. However, it does so by over predicting physiological cross-sectional areas for the masseter and pterygoid muscles and under …
Stabilization Of Thin Liquid Films Flowing Over Locally Heated Surfaces Via Substrate Topography, N Tiwari, Jm Davis
Stabilization Of Thin Liquid Films Flowing Over Locally Heated Surfaces Via Substrate Topography, N Tiwari, Jm Davis
Jeffrey M. Davis
A long-wave lubrication analysis is used to study the influence of topographical features on the linear stability of noninertial coating flows over a locally heated surface. Thin liquid films flowing over surfaces with localized heating develop a pronounced ridge at the upstream edge of the heater. This ridge becomes unstable to transverse perturbations above a critical Marangoni number and evolves into an array of rivulets even in the limit of noninertial flow. Similar fluid ridges form near topographical variations on isothermal surfaces, but these ridges are stable to perturbations. The influence of basic topographical features on the stability of the …
Linear Stability Of A Volatile Liquid Film Flowing Over A Locally Heated Surface, N Tiwari, Jm Davis
Linear Stability Of A Volatile Liquid Film Flowing Over A Locally Heated Surface, N Tiwari, Jm Davis
Jeffrey M. Davis
The dynamics and linear stability of a volatile liquid film flowing over a locally heated surface are investigated. The temperature gradient at the leading edge of the heater induces a gradient in surface tension that leads to the formation of a pronounced capillary ridge. Lubrication theory is used to develop a model for the film evolution that contains three key dimensionless groups: a Marangoni parameter (M), an evaporation number (E), and a measure of the vapor pressure driving force for evaporation (K), which behaves as an inverse Biot number. The two-dimensional, steady solutions for the local film thickness are computed …
Nonmodal And Nonlinear Dynamics Of A Volatile Liquid Film Flowing Over A Locally Heated Surface, N Tiwari, Jm Davis
Nonmodal And Nonlinear Dynamics Of A Volatile Liquid Film Flowing Over A Locally Heated Surface, N Tiwari, Jm Davis
Jeffrey M. Davis
The stability of a thin, volatile liquid film falling under the influence of gravity over a locally heated, vertical plate is analyzed in the noninertial regime using a model based on long-wave theory. The model is formulated to account for evaporation that is either governed by thermodynamic considerations at the interface in the one-sided limit or limited by the rate of mass transfer of the vapor from the interface. The temperature gradient near the upstream edge of the heater induces a gradient in surface tension that opposes the gravity-driven flow, and a pronounced thermocapillary ridge develops in the streamwise direction. …
Asymptotic Analysis Of The Selective Dip Coating Of Power-Law Fluids, N Tiwari, Jm Davis
Asymptotic Analysis Of The Selective Dip Coating Of Power-Law Fluids, N Tiwari, Jm Davis
Jeffrey M. Davis
The dip coating of a chemically micropatterned surface bearing alternating wetting and nonwetting vertical strips is analyzed for a non-Newtonian power-law fluid. Asymptotic matching is used to determine the thickness of liquid films deposited on the O(10 μm) strips at small capillary and Bond numbers. The chemical patterning that confines the fluid laterally induces a significant transverse curvature of the free-surface. The streamwise variation in this transverse curvature along the strip provides an additional contribution to the capillary pressure gradient that is not present for uniform surfaces. Consequently, the difference in the thickness of the deposited liquid film relative to …
Stability And Transient Dynamics Of Thin Liquid Films Flowing Over Locally Heated Surfaces, N Tiwari, Z Mester, Jm Davis
Stability And Transient Dynamics Of Thin Liquid Films Flowing Over Locally Heated Surfaces, N Tiwari, Z Mester, Jm Davis
Jeffrey M. Davis
The dynamics and linear stability of a liquid film flowing over a locally heated surface are studied using a long-wave lubrication analysis. The temperature gradient at the leading edge of the heater induces a gradient in surface tension that opposes the gravitationally driven flow and leads to the formation of a pronounced capillary ridge. The resulting free-surface shapes are computed, and their stability to spanwise perturbations is analyzed for a range of Marangoni numbers, substrate inclination angles, and temperature profiles. Instability is predicted above a critical Marangoni number for a finite band of wave numbers separated from zero, which is …
Transient Dynamics And Structure Of Optimal Excitations In Thermocapillary Spreading: Precursor Film Model, Jm Davis, De Kataoka, Sm Troian
Transient Dynamics And Structure Of Optimal Excitations In Thermocapillary Spreading: Precursor Film Model, Jm Davis, De Kataoka, Sm Troian
Jeffrey M. Davis
Linearized modal stability theory has shown that the thermocapillary spreading of a liquid film on a homogeneous, completely wetting surface can produce a rivulet instability at the advancing front due to formation of a capillary ridge. Mechanisms that drain fluid from the ridge can stabilize the flow against rivulet formation. Numerical predictions from this analysis for the film speed, shape, and most unstable wavelength agree remarkably well with experimental measurements even though the linearized disturbance operator is non-normal, which allows transient growth of perturbations. Our previous studies using a more generalized nonmodal stability analysis for contact lines models describing partially …
Theoretical Analysis Of The Effect Of Insoluble Surfactant On The Dip Coating Of Chemically Micropatterned Surfaces, N Tiwari, Jm Davis
Theoretical Analysis Of The Effect Of Insoluble Surfactant On The Dip Coating Of Chemically Micropatterned Surfaces, N Tiwari, Jm Davis
Jeffrey M. Davis
Microfluidic flow on chemically heterogeneous surfaces is a useful technique with applications ranging from selective material deposition to the self-assembly of nanostructures. The recent theoretical analysis by Davis [Phys. Fluids 17, 038101 (2005)] of the dip coating of a pure fluid onto vertical, wetting stripes surrounded by nonwetting regions quantified the experimentally observed deviations from the classical Landau-Levich result due to lateral confinement of the fluid by chemical surface patterning. In this present work, the analysis of dip coating of these heterogeneous surfaces is extended to a liquid containing an insoluble surfactant. Using matched asymptotic expansions based on lubrication theory …
Asymptotic Analysis Of Liquid Films Dip-Coated Onto Chemically Micropatterned Surfaces, Jm Davis
Asymptotic Analysis Of Liquid Films Dip-Coated Onto Chemically Micropatterned Surfaces, Jm Davis
Jeffrey M. Davis
The dip coating of chemically heterogeneous surfaces is a useful technique for attaining selective material deposition. For the case of vertical, wetting stripes surrounded by nonwetting regions, experiments have demonstrated that the thickness of the entrained film on the stripes is significantly different than on homogeneous surfaces because of the lateral confinement of the liquid. In the present work, the asymptotic matching of equations based on lubrication theory is used to determine the film thickness, and necessary restrictions on the capillary and Bond numbers are provided. The predictions are in excellent agreement with the existing experimental data, and the classical …
Generalized Linear Stability Of Noninertial Coating Flows Over Topographical Features, Jm Davis, Sm Troian
Generalized Linear Stability Of Noninertial Coating Flows Over Topographical Features, Jm Davis, Sm Troian
Jeffrey M. Davis
The transient evolution of perturbations to steady lubrication flow over a topographically patterned surface is investigated via a nonmodal linear stability analysis of the non-normal disturbance operator. In contrast to the capillary ridges that form near moving contact lines, the stationary capillary ridges near trenches or elevations have only stable eigenvalues. Minimal transient amplification of perturbations occurs, regardless of the magnitude or steepness of the topographical features. The absence of transient amplification and the stability of the ridge are explained on physical grounds. By comparison to unstable ridge formation on smooth, flat, and homogeneous surfaces, the lack of closed, recirculating …
Influence Of Boundary Slip On The Optimal Excitations In Thermocapillary Driven Spreading, Jm Davis, Sm Troian
Influence Of Boundary Slip On The Optimal Excitations In Thermocapillary Driven Spreading, Jm Davis, Sm Troian
Jeffrey M. Davis
Thin liquid films driven to spread on homogeneous surfaces by thermocapillarity can undergo frontal breakup and parallel rivulet formation with well-defined wavelength. Previous modal analyses have relieved the well-known divergence in stress that occurs at a moving contact line by matching the front region to a precursor film. Because the linearized disturbance operator is non-normal, a generalized, nonmodal analysis is required to probe film stability at all times. The effect of the contact line model on nonmodal stability has not been previously investigated. This work examines the influence of boundary slip on thermocapillary driven spreading using a transient stability analysis, …