Use of electrical conductance measurements in studies of the orientation of microscopic particles in stationary and flowing suspensions

This paper considers the applicability of theoretical equations for the electrical conductivity of homogeneous suspensions of identical nonconducting spheroids to studies of particle behavior in suspensions of practical interest. Results of particle shape and concentration determinations conform to theory up to volume concentrations of 0.6–0.65. The predicted relationship between particle orientation and suspension resistance is verified experimentally. The method is used to study erythrocyte orientation during blood flow in a tube of rectangular cross section. Results are consistent with observations reported by previous investigators and are in qualitative agreement with the theory of Peterlin and Stuart for the orientation distribution of microscopic spheroidal particles in dilute suspensions undergoing shear flow and subject only to thermal agitation.