Steady Infiltration from Circular Cylindrical Cavities

Abstract

AbstractThe 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, R0, ranging from 0.01 to 10. The dependence on R0 of the average infiltration rate around the cavity surface, and of the distributions of moisture content and potential, are examined. As R0 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 R0 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 R0, exceeding 50 000 for R0 = 5. An earlier small R0 approximation proves useful only for R0 ≤ 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.