PRESSURIZED STEADY-STATE FLOWS FROM SPHERICAL CAVITIES

Coupled steady state saturated-unsaturated flow from buried spherical cavities is investigated using a combined boundary element-finite element method. Earlier work on such pressurized coupled flows has been for simple two-dimensional cavities. The analysis of a simple three-dimensional flow allows the effect of dimensionality to be investigated. Detailed results for a range of pressure heads and dimensionless cavity radii and the size of the saturated regions as a function of these two parameters is illustrated. While these results show how greatly diminished the effect of gravity is in three as opposed to two dimensions, they also illustrate that the effect of gravity cannot in general be ignored. The results indicate that the ratio of the total flow from a cavity under hydrostatic pressure to the flow obtained analytically by ignoring the water depth is just a linear function of the dimensionless cavity radius. It is also shown that, while the size of the saturated region does not increase uniformly with the additional applied pressure, the relationship between the total flux from the cavity and the applied pressure is linear.