Thursday, December 4, 2025 — 2:30 pm — aula L1.7, edificio Fisica
Analytic description of the moving moisture front in soils
Abstract: The fact that moisture propagates through soil at a finite speed is confirmed by natural everyday experience as well as by controlled laboratory tests. In this talk, we rigorously derive analytical upper bounds for the speed of moisture front propagation under gravity for the solution
to the Richards equation with compactly supported initial data. The main result is an explicit criterion describing a competition between gravity and capillarity, where the dominant effect is determined by the soil’s characteristics. If capillarity prevails, the initially wet regions remain wet for all times, while if gravity is dominant, moisture travels downward at a speed that is bounded from below and above.
This is based on joint work with B. Detmann, P. Krejčí, and Y. Zhang.