Boundary element solutions of quasilinearised time-dependent infiltration

Transient quasilinearised infiltration with constant diffusivity from an axisymmetric shallow flat pond into a homogeneous semi-infinite porous medium is examined using the boundary element method. Use of the Laplace transform reduces the equation and boundary conditions to a form similar to that governing the quasilinearised steady-state flow. Numerical results showing how the flux from the pond decays in time are presented for a range of the dimensionless pond radius s likely to be found in many small-ring infiltrometer experiments. The time taken for the flux to reach near steady state is investigated, and the dependence of this time on s is examined.