Steady mixed convection boundary layer flow over a vertical flat plate in a porous medium filled with water at 4°C: case of variable wall temperature

2006 ◽  
Vol 69 (3) ◽  
pp. 359-372 ◽  
Author(s):  
S. C. Ling ◽  
R. Nazar ◽  
I. Pop
Keyword(s):  
Boundary Layer ◽  
Porous Medium ◽  
Mixed Convection ◽  
Wall Temperature ◽  
Convection Boundary Layer ◽  
Convection Boundary ◽  
Variable Wall Temperature ◽  
Layer Flow ◽  
Variable Wall ◽  
Vertical Flat Plate

Mixed Convection Boundary Layer Flow Over A Vertical Permeable Plate In A Porous Medium: Opposing Flow Case

2012 ◽  
Author(s):  
Roslinda Nazar ◽  
Ioan Pop
Keyword(s):  
Boundary Layer ◽  
Porous Medium ◽  
Mixed Convection ◽  
Wall Temperature ◽  
Boundary Layer Flow ◽  
Convection Boundary Layer ◽  
Permeable Plate ◽  
Convection Boundary ◽  
Layer Flow ◽  
Flow Case

Kajian aliran menentang bagi aliran lapisan sempadan olakan campuran mantap terhadap permukaan menegak telap dalam medium berliang dengan syarat–syarat permukaan terma yang seragam, iaitu apabila kedua–dua suhu dan fluks haba dinding adalah malar, dipertimbangkan. Nilai nombor Rayleigh bagi medium berliang diandaikan besar supaya penghampiran lapisan sempadan boleh dipertimbangkan. Dengan andaian ini, didapati masalah ini bergantung pada parameter pemindahan jisim dan parameter olakan campuran. Seterusnya, ditunjukkan bahawa persamaan–persamaan menakluk boleh diturunkan kepada bentuk keserupaan, iaitu bentuk persamaan pembezaan biasa. Persamaan–persamaan tersebut diselesaikan secara berangka menggunakan suatu skim beza terhingga tersirat yang efisien, dikenali sebagai kaedah kotak Keller. Keputusan berangka bagi geseran kulit terturun dan suhu dinding tanpa matra dibincangkan bagi nilai–nilai parameter yang dipertimbangkan. Penemuan penting dalam masalah ini adalah terdapatnya penyelesaian dual bagi persamaan menakluk lapisan sempadan dan pemisahan lapisan sempadan berlaku untuk beberapa kes. Kata kunci: Olakan campuran, lapisan sempadan, plat telap, medium berliang, aliran menentang The opposing flow case of steady mixed convection boundary layer flow over a vertical permeable surface in a porous medium with uniform thermal wall conditions, i.e. when both the wall temperature and the wall heat flux are constants, is considered. The Rayleigh number for the porous medium is assumed to be large so that the boundary layer approximation can be considered. Under these assumptions, it is found that the problem depends both on the mass transfer parameters and the mixed convection parameters. It is shown that the governing equations can be reduced to a similarity form, i.e. to ordinary differential equations. These equations are solved numerically using a very efficient implicit finite difference scheme known as the Keller–box method. Numerical results for the reduced skin friction and non–dimensional wall temperature are presented and discussed in detail for various values of the parameters of interest. An important finding of this problem is that there are dual solutions of the governing boundary layer equations and the separation of boundary layer occurs for certain cases. Key words: Mixed convection, boundary layer, permeable plate, porous medium, opposing flow

Sign in / Sign up

Export Citation Format

Share Document