The stationary hemispherical electrode under a submerged impinging jet is suggested as an experimental system that is amenable to in situ observation and has a uniform current distribution below the mass-transfer-limited value. The present work provides solutions for the steady-state boundary-layer hydrodynamics and convective diffusion. The observation of a boundary layer separation in the present work suggests that the model for convective diffusion impedance for this system must account for both the circulation region which follows the point of boundary layer separation and the boundary layer region itself. The present work is intended to provide a foundation for the design of stationary hemispherical electrode systems and for development of models for the corresponding impedance response. (C) 2004 Elsevier Ltd. All rights reserved.