The primary electroviscous effect in a suspension of spheres with thin double layers

We study the primary electroviscous effect in a suspension of spheres when the double layer thickness κ⁻¹ is small compared with the particle radius a. The case of a 1–1 symmetric electrolyte is examined using the methods of Dukhin & coworkers (1974), whilst the asymmetric electrolyte is studied along lines similar to those of O'Brien (1983). Sherwood's (1980) asymptotic results for high surface potentials and high Hartmann numbers are extended and complemented.