THE CORRELATION BETWEEN MOMENTUM AND MASS TRANSFER FOR A TURBULENT OR PERIODIC FLOW IN A CIRCULAR PIPE BY ELECTROCHEMICAL METHODS

Power spectrum densities (psd) of the velocity fluctuations in turbulent flow can be deduced from mass transfer data when the transfer function between the instantaneous mass transfer rate and the velocity in the linear regime is known. Asymptotic expressions of this transfer function at high frequencies have been previously proposed so as to characterize, in particular, the cut-off frequency af electrochemical In this work, we establish an expression of this transfer function that is valid throughout the whole frequency range for the case of a pipe flow. The nonsteady mass transfer equation for a rectangular microelectrode embedded i n the wall and placed crosswise to the mean flow direction, x, is