scholarly journals The Succession of Heat and Mass Driven Natural Convection Regimes Along a Vertical Impermeable Wall

2022 ◽  
Vol 5 (1) ◽  
pp. 9
Author(s):  
Maria Neagu
Keyword(s):  
Natural Convection ◽  
Prandtl Number ◽  
Constant Temperature ◽  
Finite Differences ◽  
Vertical Plane ◽  
Lewis Number ◽  
Scale Analysis ◽  
Governing Equations ◽  
Finite Differences Method ◽  
Impermeable Wall

This paper presents the analysis of the natural convection process that takes place near a vertical plane wall embedded in a constant temperature and linearly mass stratified fluid (the Prandtl number and the Smith number are smaller than 1.0, while the Lewis number is greater than 1.0). The wall has a constant temperature, while the flux of a certain constituent is constant at this boundary. The scale analysis and the finite differences method are used as techniques of work. The scale analysis proves the existence, at equilibrium, of heat and/or mass driven convection regimes along the wall. The finite differences method is used solve the governing equations and to verify the scale analysis results using two particular parameters sets.

scholarly journals Double-Diffusive of Natural Convection in an Inclined Porous Square Domain Generalized Model

2019 ◽  
Vol 12 (3) ◽  
pp. 151-160
Author(s):  
Khaled Al-Farhany ◽  
A. Turan
Keyword(s):  
Natural Convection ◽  
Lewis Number ◽  
Boussinesq Approximation ◽  
Darcy Number ◽  
Governing Equations ◽  
Simpler Algorithm ◽  
Wide Range ◽  
Finite Volume Approach ◽  
Buoyancy Ratio ◽  
Double Diffusive

Numerical investigate of double-diffusive natural convection in an inclined porous square. Two opposing walls of the square cavity are adiabatic; while the other walls are, kept at constant concentrations and temperatures. The Darcy–Forchheimer–Brinkman model is used to solve the governing equations with the Boussinesq approximation. A code written in FORTRAN language developed to solve the governing equations in dimensionless forms using a finite volume approach with a SIMPLER algorithm. The results presented in U-velocity and V-velocity, isotherms, iso-concentration, streamline, the average Nusselt number, and the average Sherwood number for different values of the dimensionless parameters. A wide range of these parameters have been used including; Darcy Number, modified Rayleigh number, Lewis number, buoyancy ratio, and inclination angle.  The results show that for opposite buoyancy ratio (N≤-1), the Nu decreases when the Le increases and the Sh increase when the Le increases. For an (N>0), the Nu increases when the Le increases until Le is equal to 1 and then it decreases, also Sh increases when the Le increases

Transient natural convection in a partially open trapezoidal cavity filled with a water-based nanofluid under the effects of Brownian diffusion and thermophoresis

2018 ◽  
Vol 28 (3) ◽  
pp. 606-623 ◽  
Author(s):  
Nadezhda S. Bondareva ◽  
Mikhail A. Sheremet ◽  
Hakan F. Öztop ◽  
Nidal Abu-Hamdeh
Keyword(s):  
Natural Convection ◽  
Lewis Number ◽  
Brownian Diffusion ◽  
Governing Equations ◽  
Nanofluid Flow ◽  
Content Type ◽  
Average Temperature ◽  
Flow And Heat Transfer ◽  
Water Based ◽  
Buoyancy Ratio

Purpose The purpose of this paper is to study about the natural convection of water-based nanofluid in a partially open trapezoidal cavity under the influence of Brownian diffusion and thermophoresis. Design/methodology/approach Governing equations formulated in dimensionless stream function – vorticity variables – have been solved by finite difference method with a homemade code C++. Effects of Rayleigh number (Ra = 50-1,000), Lewis number (Le = 10-1,000), buoyancy-ratio parameter (Nr = 0.1-5.0), Brownian motion parameter (Nb = 0.1, 1.0) and thermophoresis parameter (Nt = 0.1, 1.0) on nanofluid flow and heat transfer have been studied. Findings It is found that high values of Rayleigh and Lewis numbers lead to the homogenization of nanoparticles distributions. For high values of Nt and Nb, heating is more essential and the cavity average temperature rises. Originality/value The originality of this work is to analyze natural convection in an open-sided trapezoidal cavity with Brownian diffusion and thermophoresis.

Unsteady Natural Convection Heat Transfer Past a Vertical Flat Plate Embedded in a Porous Medium Saturated With Fractional Oldroyd-B Fluid

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Jinhu Zhao ◽  
Liancun Zheng ◽  
Xinxin Zhang ◽  
Fawang Liu ◽  
Xuehui Chen
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Porous Medium ◽  
Natural Convection ◽  
Prandtl Number ◽  
Fractional Derivative ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Elastic Effect

This paper investigates natural convection heat transfer of generalized Oldroyd-B fluid in a porous medium with modified fractional Darcy's law. Nonlinear coupled boundary layer governing equations are formulated with time–space fractional derivatives in the momentum equation. Numerical solutions are obtained by the newly developed finite difference method combined with L1-algorithm. The effects of involved parameters on velocity and temperature fields are presented graphically and analyzed in detail. Results indicate that, different from the classical result that Prandtl number only affects the heat transfer, it has remarkable influence on both the velocity and temperature boundary layers, the average Nusselt number rises dramatically in low Prandtl number, but increases slowly with the augment of Prandtl number. The maximum value of velocity profile and the thickness of momentum boundary layer increases with the augment of porosity and Darcy number. Moreover, the relaxation fractional derivative parameter accelerates the convection flow and weakens the elastic effect significantly, while the retardation fractional derivative parameter slows down the motion and strengthens the elastic effect.

scholarly journals 3-dimensional analysis of holographic memories based on photopolymers using finite differences method

2006 ◽  
Author(s):  
Sergi Gallego ◽  
Manuel F. Ortuño ◽  
Cristian Neipp ◽  
Andrés Márquez ◽  
Augusto Beléndez ◽  
...  
Keyword(s):  
Dimensional Analysis ◽  
Finite Differences ◽  
3 Dimensional ◽  
Finite Differences Method ◽  
Holographic Memories
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