Zienkiewicz O.C., Taylor R.L. Vol. 3. The finite - tiera.ru

θ = 0.5
θ = 0.5
θ = 0.5
g
g
α = 0°
θ = –0.5
θ = –0.5
5.3.3 Buoyancy in porous media ¯ows
g
α = 60°
α = 0°
Streamlines
θ = –0.5
Studies of convective motion and heat transfer in a porous medium are essential to
understand many engineering problems including solidi®cation of alloys, convection
over heat exchanger tubes, thermal insulations, packed and ¯uidized beds, etc. We
give a brief introduction to such ¯ows in this section.
Porous medium ¯ows are di€erent from those of single-phase ¯uid ¯ows due to the
presence of the solid particles which for our purpose are considered as rigidly ®xed in
space. Many textbooks on porous medium ¯ows are already available. 42;43 Similar
porous media occur in problems of geomechanics in which generally the motion of
θ = 0.5
θ = 0.5
θ = 0.5
g
g
α = 0°
g
α = 60°
α = 0°
Isotherms
Buoyancy driven ¯ows 157
Fig. 5.10 Natural convection in a square enclosure. Streamlines and isotherms for different gravity directions,
Ra ˆ 10 6 .
θ = –0.5
θ = –0.5
θ = –0.5