scholarly journals Numerical Solution of Energy Equation in Porous Channels under Effects of Radiation Field

2021 ◽  
pp. 3620-3633
Author(s):  
Ala'a A. Hammodat ◽  
Osama T. Al-Bairaqdar ◽  
Abida T. Hammodat
Keyword(s):  
Finite Difference Methods ◽  
Radiation Heat Transfer ◽  
Vertical Channel ◽  
Dimensional System ◽  
Horizontal Magnetic Field ◽  
Heat Temperature ◽  
Linear Partial Differential Equations ◽  
Alternating Direction ◽  
Two Phases ◽  
Effects Of Radiation

     In this paper, we built a mathematical model for convection and thermal radiation heat transfer of fluid flowing through a vertical channel with porous medium under effects of horizontal magnetic field (MF) at the channel. This model represents a 2-dimensional system of non-linear partial differential equations. Then, we solved this system numerically by finite difference methods using Alternating Direction Implicit (ADI) Scheme in two phases (steady state and unsteady state). Moreover, we found the distribution and behaviour of the heat temperature inside the channel and studied the effects of Brinkman number, Reynolds number, and Boltzmann number on the heat temperature behaviour. We solved the system by building a computer program using MATLAB.

Effect of Insulated/Uninsulated Channel Walls on Heat Transfer From a Horizontal Finned Tube in a Vertical Channel

1987 ◽  
Vol 109 (2) ◽  
pp. 388-391 ◽  
Author(s):  
E. M. Sparrow ◽  
M. A. Ansari
Keyword(s):  
Heat Transfer ◽  
Radiation Heat Transfer ◽  
Vertical Channel ◽  
Finned Tube ◽  
Radiation Heat ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Metallic Sheet ◽  
Rayleigh Numbers ◽  
Metal Wall

Measurements were made of the combined natural convection and radiation heat transfer from a horizontal finned tube situated in a vertical channel open at the top and bottom. In one set of experiments, both walls of the channel were heavily insulated, while in a second set of experiments, one of the insulated walls was replaced by an uninsulated metallic sheet. In general, the heat transfer coefficients were found to be lower with the metal wall in place, but only moderately. With the finned tube situated at the bottom of the channel, the differences in the heat transfer coefficients corresponding to the two types of walls were only a few percent. When the tube was positioned at the mid-height of the channel, larger differences were encountered, but in the practical range of Rayleigh numbers, the differences did not exceed 5 percent.

Review Lectures on Senescence: I. The Causes of Aging

2001 ◽  
Vol 2001 (1) ◽  
Author(s):  
J. Maynard Smith
Keyword(s):  
Aging Process ◽  
Somatic Mutations ◽  
Cellular Level ◽  
Temperature Dependent ◽  
Theories Of Aging ◽  
Organ Systems ◽  
Two Phases ◽  
Effects Of Radiation ◽  
The Individual ◽  
Do So

Aging processes are defined as those that increase the susceptibility of individuals as they grow older to the factors that may cause death. Various possible theories of aging are considered, and evidence that may help to decide between them is discussed. Changes in different organ systems may be merely symptoms of some single aging process, or they may be largely independent and synchronized by natural selection. Even if different organ systems age independently, they may do so as a result of similar changes at a cellular level. Cellular theories of aging may have to take into account the effects of selection between the cells in a tissue. The effects of radiation and somatic mutation theories of aging are discussed. It is suggested that radiation shortens life by inducing somatic mutations but that normal aging is not to any important extent caused by somatic mutations, although it may result from changes in cells that have effects on the physiology of the individual similar to those of somatic mutations. Evidence is presented that in Drosophila and in mice there are two phases in the life-span. In Drosophila , there is an initial “aging” phase, which is irreversible and occurs at a rate approximately independent of temperature, and a second “dying” phase, which is temperature-dependent in rate and reversible at lower temperatures. Reproduced by permission. J. Maynard Smith, Review Lectures on Senescence: I. The Causes of Aging. Proc. R. Soc. London Ser. B 157 , 115-127 (1962).

scholarly journals Maximum Norm Error Estimates of ADI Methods for a Two-Dimensional Fractional Subdiffusion Equation

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Yuan-Ming Wang
Keyword(s):  
Finite Difference Methods ◽  
Maximum Norm ◽  
Two Dimensional ◽  
Alternating Direction Implicit ◽  
Truncation Errors ◽  
Alternating Direction ◽  
Difference Methods ◽  
Subdiffusion Equation ◽  
Adi Methods ◽  
Norm Error

This paper is concerned with two alternating direction implicit (ADI) finite difference methods for solving a two-dimensional fractional subdiffusion equation. An explicit error estimate for each of the two methods is provided in the discrete maximum norm. It is shown that the methods have the same order as their truncation errors with respect to the discrete maximum norm. Numerical results are given to confirm the theoretical analysis results.

Lattice Boltzmann modelling for multiphase bubble flow in electroconducting liquids

2017 ◽  
Vol 36 (2) ◽  
pp. 401-407
Author(s):  
Andrejs Tatulcenkovs ◽  
Andris Jakovics ◽  
Egbert Baake ◽  
Bernard Nacke
Keyword(s):  
Lattice Boltzmann ◽  
Vertical Channel ◽  
High Ratio ◽  
Lattice Boltzmann Model ◽  
Bubble Flow ◽  
Content Type ◽  
Flow Motion ◽  
Bubble Interaction ◽  
Two Phases ◽  
Density Ratios

Purpose The purpose of this paper is to the study the multiphase bubbles flow motion in a vertical channel with an electroconducting liquid without and under the influence of a magnetic field. Design/methodology/approach For numerical calculations, the lattice Boltzmann method (LBM) is used, which is based on the kinetic theory for solving fluid mechanics and other physical problems. The phase-field lattice Boltzmann model is developed to simulate the behaviour of multiphase bubble–bubble interaction while rising in the fluid with high density ratios. Findings The behaviour of the rising bubble flow in a rectangular column of two phases is investigated with the two-dimensional LBM. Originality/value The multiphase flow in electroconducting liquids with high ratio of density is studied using the LBM.

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