Chekifi. T^1,2, Dennai. B¹, Khelfaoui. R¹

FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.3, pp. 205-220, 2015, DOI:10.3970/fdmp.2015.011.205

Abstract Droplet generation, splitting and sorting are investigated numerically in the framework of a VOF technique for interface tracking and a finite-volume numerical method using the commercial code FLUENT. Droplets of water-in-oil are produced by a flow focusing technique relying on the use of a microchannell equipped with an obstacle to split the droplets. The influence of several parameters potentially affecting this process is investigated parametrically towards the end of identifying "optimal" conditions for droplet breakup. Such parameters include surface tension, the capillary number and the main channel width. We show that the capillary number plays More >

Shuce Zhang¹, Xueheng Tao^1,2,3, Jinshi Lu^1,2, Xuejun Wang^1,2, ZhenhuaZeng⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.2, pp. 143-155, 2015, DOI:10.3970/fdmp.2015.011.143

Abstract Three different kinds of nozzles, normally used in industrial processes for the cleaning of material surface by means of water jets at high pressure (a Cylindrical Contracting, a Taper Contracting and Stepped nozzle), are numerically simulated with the express intent to optimize the related efficiency (cleaning effectiveness). Although some of them are found to display interesting properties, simulation results indicate that a helix nozzle displays the best jetting performances. It is shown that, as compared to improvements obtained by simply changing the jetting angle, revolving the fluid released from the helix nozzle can be used More >

Edoardo Gino Macchi^* , Giovanni Braschi, Mario Gallati

Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-8, 2014, DOI:10.5098/hmt.5.20

Abstract Radiofrequency thermal ablation (RFTA) is a medical procedure currently widely adopted for liver tumors treatment. Its outcome is strongly influenced by temperature distribution near the RF applicator therefore continuous measurements are required both to validate RFTA numerical models and to better control the outcome of the procedure. The space-time evolution of the thermal field during RFTA on ex vivo porcine liver tissue has been measured by infrared thermal imaging in different experimental setups. A three-dimensional simulation of the whole experiment reproduces all the features of the thermal field measurements and validates the proposed measurement methodology. More >

Manoj Kr. Triveni^* , Dipak Sen, RajSekhar Panua

Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-8, 2014, DOI:10.5098/hmt.5.12

Abstract A numerical investigation has been performed for heat transfer analysis in a right-angled triangular enclosure filled with water. The side wall of the enclosure is maintained at high temperature compare to the base wall while hypotenuse is kept thermally insulated. Two - dimensional steady-state continuity, momentum and energy equations along with the boussinesq approximation are solved by finite volume method using commercial available software, FLUENT 6.3. The computational results are shown in terms of isotherms, streamlines and velocity contour for Rayleigh number (10⁵ ≤ Ra ≤ 10⁷ ). The heat transfer is presented in terms of More >

H. Y. Fang^1,2,3, J. Liu⁴, F. M. Wang^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.99, No.6, pp. 473-490, 2014, DOI:10.32604/cmes.2014.099.473

Abstract Construction of electromagnetic wave propagation model in layered pavement structure is a key step in back analysis of ground penetrating radar (GPR) echo signal. The precise integration method (PIM) is a highly accurate, efficient, and unconditionally stable algorithm for solving 1-order ordinary differential equations. It is quite suitable for dealing with problems of wave propagation in layered media. In this paper, forward simulation of GPR electromagnetic wave propagating in homogeneous layered pavement structure is developed by employing PIM. To verify the performance of the proposed algorithm, simulated GPR signal is compared with the measured one. More >

F. Mechighel^1,2,3, N. Armour⁴, S. Dost⁴, M. Kadja³

CMES-Computer Modeling in Engineering & Sciences, Vol.97, No.1, pp. 53-80, 2014, DOI:10.3970/cmes.2014.097.053

Abstract Numerical simulations were carried out to explain the behavior exhibited in experimental work on the dissolution process of silicon into a germanium melt. The experimental work utilized a material configuration similar to that used in the Liquid Phase Diffusion (LPD) and Melt-Replenishment Czochralski (Cz) growth systems. The experimental dissolution system was modeled by considering axisymmetric and three-dimensional (3-D) domains. In both cases, the governing equations, namely conservation of mass, momentum balance, energy balance, and solute transport balance, were solved using the Finite Element Method.
Measured concentration profiles and dissolution heights from the experiment samples showed that… More >

S. Saha Ray¹, A. K. Gupta²

CMES-Computer Modeling in Engineering & Sciences, Vol.103, No.5, pp. 315-341, 2014, DOI:10.3970/cmes.2014.103.315

Abstract In this paper, an efficient numerical schemes based on the Haar wavelet method are applied for finding numerical solution of nonlinear third-order modified Korteweg-de Vries (mKdV) equation as well as modified Burgers' equations. The numerical results are then compared with the exact solutions. The accuracy of the obtained solutions is quite high even if the number of calculation points is small. More >

Guoqing Yang¹, Baotong Li^2,3, Yang Wang², Jun Hong²

CMES-Computer Modeling in Engineering & Sciences, Vol.103, No.4, pp. 251-279, 2014, DOI:10.3970/cmes.2014.103.251

Abstract Mechanical behaviors arising at the contact interface largely depend on its surface topographies, particularly when it comes to rough surfaces. A numerical simulation based on an appropriate characterization of rough surfaces especially in terms of three dimensional can be of great significance when it comes to capturing the deformation patterns of micro-scale contacts. In this paper, a simple and practical scheme is developed to generate 3D rough surfaces and to analyze and evaluate the contact characteristics. Firstly amplitude and spatial statistical characterizations of asperities are introduced to avert from the redundancy of topography data caused… More >

S. Hamimid^1,2, M. Guellal¹

FDMP-Fluid Dynamics & Materials Processing, Vol.10, No.3, pp. 377-393, 2014, DOI:10.3970/fdmp.2014.010.377

Abstract Combined laminar natural convection and surface radiation in a differentially heated square cavity has been investigated by a finite volume method through the concepts of staggered grid and SIMPLER approach. A power scheme has been also used in approximating advection–diffusion terms, determining the view factors by means of analytical expressions. The effect of emissivity on temperature and velocity profiles within the enclosure has been analyzed. In addition, results for local and average convective and radiative Nusselt numbers are presented and discussed for various conditions. More >

A. Najjaran^*, Ak. Najjaran, A. Fotoohabadi, A.R. Shiri

Frontiers in Heat and Mass Transfer, Vol.4, No.1, pp. 1-5, 2013, DOI:10.5098/hmt.v4.1.3003

Abstract In this paper, the aim is obtaining convection coefficient of human body. This field of study is essential in study of ventilation systems, astronauts’ clothes and any other fields in which human body is the main concern. At first a 3D human body has been designed by unstructured grids. Feet and hands are stretched completely in considered sample. Two postures (standing and supine) are considered for body. Soles and the back of entire body are considered in contact with the ground respectively in these postures. Other parts of human body are exposed to surrounding air. More >