The possibilities of generalizing the dispersion equations of flow through porous media are investigated. Based on the hypothesis (‘Bear's hypothesis’) that only that part of each velocity component is of significance which is either parallel or normal to the mean flow direction, the general form of the dispersion is deduced. The dispersivity becomes a tensor of the fourth rank. It has such symmetry properties that it contains only 36 instead of 81 independent components in the general case of an anisotropic porous medium. In isotropic media there are only two dispersivity constants. The latter result had already been deduced by Nikolaevskii. The connection of the dispersivity tensor with a tensor which had previously been constructed by Bear is demonstrated.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.