Absorption of Water Into Porous Blocks of Various Shapes and Sizes

Approximate solutions are presented for absorption of water into porous spherical, cylindrical, and slablike blocks whose characteristic curves are of the van Genuchten‐Mualem type. The solutions are compared to numerical simulations of absorption into blocks of the Topopah Spring member (Paintbrush tuff) from the site of the proposed nuclear waste repository at Yucca Mountain, Nevada. Guided by these results, a scaling law, based on the ratio of surface area to volume, is then proposed for predicting the rate of absorption into irregularly shaped blocks. This scaling law is tested against a numerical simulation of absorption into an irregularly shaped, 2‐dimensional polygonal block and is shown to be a good approximation.