Turbulence, extreme limits

To appreciate that deviation from the Levich equation is likely to stem from non-limiting currents (the overpotential rj is not extreme enough), breakdown of mass transport ( j is too extreme) and turbulent flow. 

In the limit of extreme turbulence, when eddies of fresh solution are rapidly swept into the immediate vicinity of the interface, neither the laminar sublayer nor a stationary surface can exist the diffusion path may, according to Kishinevskii, become so short that diffusion is no longer rate-controlling, and consequently for such liquid-phase transfer (14)... 

Due to the constant flow through the measurement cell the response time is extremely short. However, the constant flow creates turbulence in the cell, which the microphone detects as noise. Therefore the detection limit in a continuous flow system is higher than in a discrete sampling system. 

The price paid for trying to access shorter time-scales is precision. Analogous problems arise with precision when steady-state methods are pushed to their limits (e.g. turbulent flow conditions associated with extremely... 

The atmospheric corrosion rate is usually said to be under mixed control, with the rate determined both by the delivery rate of corrodents to the surface and by the reaction rate of reactants with the surface. Two extreme situations can be identified. Under highly turbulent and weU-stirred airflow conditions, there is no limitation in transport rate and the corrosion rate is only determined by surface reaction rates. On the other hand, when the corroding surface acts as an ideal absorber for corrodents, there is no limitation in surface reaction rate and the corrosion rate will be limited by transport processes to the surface. 

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