Tx. Lu et al., WATER-MOVEMENT IN GLASS BEAD POROUS-MEDIA .3. THEORETICAL ANALYSES OFCAPILLARY RISE INTO INITIALLY DRY MEDIA, Water resources research, 31(1), 1995, pp. 11-18
This paper presents a theoretical analysis of the experimental evidenc
e reported in papers 1 and 2 (Lu et al., this issue (a, b)). The analy
sis of force is conducted on spherical particles serving as an idealiz
ed porous medium. Four close packing conditions were studied and two m
odels were developed to describe liquid movement in glass bead porous
media. According to the analysis of forces acting on the contact point
of gas-liquid interface, the direction as well as the magnitude of th
e total surface tensile force changes in contrast to a constant total
surface tensile force acting in a capillary tube. It is shown that the
velocity of the liquid plays an important role during capillary rise
into porous media. Equations for the height and velocity of capillary
rise into initially dry porous media are given for four different geom
etries of close packing. The models and equations present an improved
explanation of the Haines' ''jump'' phenomenon and the instability obs
erved in experiments of capillary rise in porous media.