Convection Currents in Porous Media. III. Extended Theory of the Critical Gradient

摘要: The theory of the critical gradient for onset thermal convection in a fluid entrapped porous medium is extended to allow exponential dependence viscosity upon temperature and non‐linear vertical temperature‐distributions which characterize transients heat flow. Although there are approximations mathematical treatment, agrees rather well with experimental data, as simple does not certain instances. New data reported gradient, obtained largely silicone fluids unconsolidated sands.