Steady Infiltration from Circular Cylindrical Cavities

The problem of quasilinearized steady infiltration from circular cylindrical cavities, with the moisture potential fixed at the cavity surface, is solved exactly. Solutions are presented numerically and graphically for values of the dimensionless cavity radius, R 0 , ranging from 0.01 to 10. The dependence on R 0 of the average infiltration rate around the cavity surface, and of the distributions of moisture content and potential, are examined. As R 0 increases, the effects of gravity on the phenomenon increasingly dominate those of capillarity. Gravity very strongly distorts the moisture distribution from the symmetry produced by capillarity alone: for R 0 as small as 0.01, the depth of the effectively wetted region exceeds 250 times its horizontal width on the cavity center line; and the ratio increases rapidly with R 0 , exceeding 50 000 for R 0 = 5. An earlier small R 0 approximation proves useful only for R 0 ≤ 0.2. The cavity flow, evaluated by the present analysis, may be combined with the line source solution to give approximate results useful for the region deeper than 50 radii below the cavity.