Asghar Esmaeeli¹

FDMP-Fluid Dynamics & Materials Processing, Vol.1, No.1, pp. 63-80, 2005, DOI:10.3970/fdmp.2005.001.063

Abstract We use direct numerical simulations to study phase distribution of bubbles under terrestrial and microgravity conditions. The full Navier-Stokes and energy equations, for the flows inside and outside the bubbles, are solved using a front tracking/finite difference technique. Both nearly spherical and deformable bubbles are considered. For buoyancy-driven flows, spherical bubbles at Re = O(10) and deformable ones at Re = O(100) exhibit a uniform spatial distribution at quasi steady-state conditions, while nearly spherical bubbles at Re = O(100) form horizontal rafts. Bubbles, driven by thermocapillary effects in microgravity, also form horizontal rafts, but due to an entirely different mechanism.… More >

A.Yu. Gelfgat¹, A. Rubinov², P.Z. Bar-Yoseph², A. Solan²

FDMP-Fluid Dynamics & Materials Processing, Vol.1, No.1, pp. 21-32, 2005, DOI:10.3970/fdmp.2005.001.021

Abstract The three-dimensional instability of the thermocapillary convection in cylindrical undeformable floating zones heated laterally is studied numerically. Different types of the boundary conditions, including radiation heating, linearized radiation and prescribed heat flux are used in the calculation. Stability diagrams showing the Prandtl number dependence of the critical Marangoni numbers that represent the thermocapillary forcing for different heating conditions are reported. It is shown that the primary instability of initially axisymmetric thermocapillary flows is defined mainly by the total amount of heat supplied through the heated side surface. The way in which the heat is supplied has a less significant effect… More >

Mohamed I. A. Othman^1,2,3, W. M. Hasona^2,4, Nehal T. Mansour^2,5

CMC-Computers, Materials & Continua, Vol.45, No.3, pp. 203-220, 2015, DOI:10.3970/cmc.2015.045.203

Abstract The problem of the generalized thermoelastic medium for three different theories under the effect of a gravitational field is investigated. The Lord- Shulman, Green-Naghdi III, three-phase-lag theories are discussed with twotemperature. The normal mode analysis is used to obtain the analytical expressions of the displacement components, force stress, thermodynamic temperature and conductive temperature. The numerical results are given and presented graphically, when the thermal force is applied. Comparisons are made with the results predicted by three-phase-lag model, Green-Naghdi III and Lord-Shulman theories in the presence and absence of gravity as well as two temperature. More >

Marcello Lappa ¹

CMC-Computers, Materials & Continua, Vol.2, No.1, pp. 51-64, 2005, DOI:10.3970/cmc.2005.002.051

Abstract A possible approach for the investigation of a number of aspects related to the processing of immiscible alloys, made possible by recent progress in both fields of moving boundary (VOF) methods and speed of computers, is discussed. It can capture in a single numerical treatment and without limiting assumptions both macroscopic information (i.e. the macrophysical problem, heretofore treated in terms of population dynamics) and microscopic details (i.e. the microphysical problem, heretofore treated within the framework of boundary integral methods and/or under the assumption of nondeformable drops). The role played by coalescence in changing the Marangoni migration velocity is discussed together… More >