Marangoni convection induced by a nonlinear temperature-dependent surface tension

1986 ◽  
Vol 47 (1) ◽  
pp. 23-29 ◽  
Author(s):  
A. Cloot ◽  
G. Lebon
Keyword(s):  
Surface Tension ◽  
Marangoni Convection ◽  
Temperature Dependent ◽  
Nonlinear Temperature

scholarly journals A new boundary element algorithm for modeling and simulation of nonlinear thermal stresses in micropolar FGA composites with temperature-dependent properties

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Mohamed Abdelsabour Fahmy
Keyword(s):  
Modeling And Simulation ◽  
Boundary Element ◽  
Thermal Stresses ◽  
Computation Time ◽  
Functionally Graded ◽  
Temperature Dependent ◽  
Time Step ◽  
Kirchhoff Transformation ◽  
Nonlinear Temperature ◽  
Temperature Dependent Properties

AbstractThe main aim of this article is to develop a new boundary element method (BEM) algorithm to model and simulate the nonlinear thermal stresses problems in micropolar functionally graded anisotropic (FGA) composites with temperature-dependent properties. Some inside points are chosen to treat the nonlinear terms and domain integrals. An integral formulation which is based on the use of Kirchhoff transformation is firstly used to simplify the transient heat conduction governing equation. Then, the residual nonlinear terms are carried out within the current formulation. The domain integrals can be effectively treated by applying the Cartesian transformation method (CTM). In the proposed BEM technique, the nonlinear temperature is computed on the boundary and some inside domain integral. Then, nonlinear displacement can be calculated at each time step. With the calculated temperature and displacement distributions, we can obtain the values of nonlinear thermal stresses. The efficiency of our proposed methodology has been improved by using the communication-avoiding versions of the Arnoldi (CA-Arnoldi) preconditioner for solving the resulting linear systems arising from the BEM to reduce the iterations number and computation time. The numerical outcomes establish the influence of temperature-dependent properties on the nonlinear temperature distribution, and investigate the effect of the functionally graded parameter on the nonlinear displacements and thermal stresses, through the micropolar FGA composites with temperature-dependent properties. These numerical outcomes also confirm the validity, precision and effectiveness of the proposed modeling and simulation methodology.

Ferrohydrodynamic Capillary Convection

2018 ◽  
Vol 11 (2) ◽  
Author(s):  
Francisco J. Arias ◽  
Salvador A. De Las Heras
Keyword(s):  
Magnetic Field ◽  
Surface Tension ◽  
Concentration Gradient ◽  
Deductive Reasoning ◽  
Marangoni Convection ◽  
Marangoni Effect ◽  
Magnetic Fluids ◽  
Homogeneous Magnetic Field ◽  
Gradient Field ◽  
Two Fluids

Abstract In this work, consideration is given to capillary convection on ferrofluids from the concentration gradient induced when a nonhomogeneous magnetic field is applied. It is known that mass transfer along an interface between two fluids can appear due to a gradient of the surface tension in the so-called Marangoni effect (or Gibbs–Marangoni effect). Because the surface tension is both thermal and concentration dependent, Marangoni convection can be induced by either a thermal or a concentration gradient, where in the former case, it is generally referred as thermocapillary convection. Now, it has been theoretically and experimentally demonstrated that a ferrofluid under the action of a non-homogeneous magnetic field can induce a concentration gradient of suspended magnetic nanoparticles, and also the effect of Fe3O4 nanoparticles on the surface tension has been measured. Therefore, by deductive reasoning and taking into account the above mentioned facts, it is permissible to infer ferrohydrodynamic capillary convection on magnetic fluids under the presence of a magnetic gradient field. Utilizing a simplified physical model, the phenomenon was investigated and it was found that ferrohydrodynamic-Marangoni convection could be induced with particle size in the range up to 10 nm, which is the range of magnetic fluids to escape magnetic agglomeration.

Surface Deformation and Thermal Convection in Electrostatically-Positioned Droplets Under Microgravity

1999 ◽  
Author(s):  
Suping Song ◽  
Ben Q. Li
Keyword(s):  
Surface Tension ◽  
Temperature Gradient ◽  
Laser Heating ◽  
Surface Deformation ◽  
Marangoni Convection ◽  
Stokes Equations ◽  
Energy Balance Equation ◽  
Droplet Surface ◽  
Fundamental Study ◽  
Recirculating Flow

Abstract Electrostatically positioned droplets are very useful for the fundamental study of solidification phenomena and the measurement of thermal physical properties. This paper descries a numerical analysis of surface deformation and surface tension driven flows in electrostatically positioned droplets in microgravity. The analysis is based on a fully coupled boundary element and finite element solution of the Maxwell equations, the Navier-Stokes equations and the energy balance equation. Results show that an applied electrostatic field results in a nonuniform electric stress distribution along the droplet surface, which, combined with surface tension, causes the droplet to deform into an ellipsoidal shape in microgravity. Laser heating induces a non-uniform temperature distribution in the droplet, which in turn produces Marangoni convection in the droplet. It is found that the viscous stress contribution to the deformation is small for a majority of cases. Also, a higher temperature gradient produces a stronger Marangoni convection in droplets with higher melting points that require more laser power. The internal recirculating flow may be reduced by more uniform laser heating. During the undercooling of the droplet, both temperature and fluid flow fields evolve in time such that the temperature gradient and the tangential velocities along the droplet surface subside in magnitude and reverse their directions.

Simplified Analysis of Heat-Curved Steel Girders

2003 ◽  
Vol 1861 (1) ◽  
pp. 101-114
Author(s):  
Antoine N. Gergess ◽  
Rajan Sen
Keyword(s):  
Cross Section ◽  
High Performance ◽  
Three Dimensional ◽  
Nonlinear Finite Element ◽  
Steel Bridge ◽  
Temperature Dependent ◽  
Iterative Analysis ◽  
Nonlinear Temperature ◽  
Simplified Analysis ◽  
Single Heating

Heat curving is commonly used in the fabrication of curved structural steel bridge girders. A two-dimensional superposition analysis known as the Duhamel Analogy was used for numerical modeling in the development of the AASHTO code provisions. This iterative analysis can take into consideration multiple heating–cooling cycles, initial residual stresses, temperature-dependent material properties, and the nonlinear temperature distribution across the girder cross section. A simplified analysis based on the Duhamel Analogy that can be carried out by using hand calculations is described. The curvatures obtained by this method are within 15% of the measured curvatures, which are very comparable to the results obtained by using the Duhamel Analogy or the three-dimensional, nonlinear, finite element solution. The background, basis, and steps required for the proposed analysis are described; and an illustrative numerical example is presented. The proposed analysis may be used to estimate curvatures or to determine the maximum fabrication temperature and the heating width for a single heating–cooling cycle for steels such as high-performance steel not covered by the current AASHTO provisions.

Lielmezs–Herrick correlation for the temperature-dependent surface tension of hydrocarbons

2016 ◽  
Vol 30 (23) ◽  
pp. 1650154 ◽  
Author(s):  
Cuihua Zhang ◽  
Huili Yi ◽  
Jianxiang Tian
Keyword(s):  
Surface Tension ◽  
The Other ◽  
Temperature Dependent ◽  
Two Parameters ◽  
Two Parameter

In this paper, we analyzed the ability of Lielmezs–Herrick (LH) correlation for the temperature-dependent surface tension of 28 hydrocarbons. We found that compared with other published correlations, the original LH correlation stands well only for four fluids. By using new data in REFPROP database, we refitted the two parameters of LH correlation. Two sets values are obtained. One is the updated corresponding state LH correlation, which is fluid independent. The other is the two-parameter LH correlation, which is fluid dependent. We found that the former clearly improves the accuracy of the original LH correlation and the latter is the best among all of the correlations we know.

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