2021/04/16 by Triadis, Dimetre, Broadbridge, Philip
#FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Geophysics (physics.geo-ph)
paper · doi:10.48550/arxiv.2104.15009
An analytical solution of the nonlinear Richards equation is presented, for one-dimensional infiltration into a soil of uniform initial moisture content subject to a constant depth of surface ponded water. Adopted mathematical forms of the soil water diffusivity and conductivity are flexible enough to model a range of real soils. The solution takes the form of a power series in √ t, but is observed to converge not only for small times but also for relatively large times at which travelling-wave-like behavior is evident. The solution is used to tabulate exact infiltration coefficients with higher-order corrections as the natural nonlinear limit of soil properties is approached. Previously published approximate solutions that apply for a wide range of soil properties are tested against the exact solution and found to be sufficiently accurate.