On Infiltration and Infiltration Characteristic Times

In his seminal paper on the solution of infiltration equation, Philip (1969), https://doi.org/10.1016/b978-1-4831-9936-8.50010-6 proposed a gravity time, tgrav, to estimate practical convergence time and domain validity infinite series expansion, TSE, for describing transient state. The parameter tgrav refers point in where is dominated equally by capillarity as derived from first two (dominant) terms TSE. Evidence suggests that applicability truncated two-term equation has limit requiring higher-order TSE better describe process times exceeding limit. Since conceptual definition valid regardless model used, we opted reformulate using analytic implicit Parlange et al. (1982), https://doi.org/10.1097/00010694-198206000-00001 all related Our ensure given accuracy approximations states, while also providing insight about needed reach steady addition roles soil sorptivity (S) saturated (Ks) initial (Ki) hydraulic conductivities, explored effects specific shape β, involved Parlange's type soil, behavior tgrav. We show reformulated (notably F(β) β-dependent function) three larger than classical . differences between tgrav,Philip increase fine-textured soils, attributed attain steady-state thus i + inferring properties. Results indicator tgrav,Philip. For attainment infiltration, suitable coarse-textured soils. Still neither nor are soils which too conservative short. Using will improve predictions parameters (particularly Ks) data compared