The fluctuations of potential, current, and electrolyte resistance generated by uniform corrosion processes on a mild-steel rotating disk electrode in a mixture of paraffin oil and brine have been measured. The mixture composition has been varied to assess the possibility of characterizing the type of hydrodynamic flow from the noise measurements. Results have shown that, contrary to electrochemical potential and current noise, electrolyte resistance fluctuations, both in the time and frequency domains, are a highly sensitive parameter for monitoring changes in the flow composition.