Spectral analysis of wall turbulence with a bicircular electrochemical probe

Near-wall turbulence in drag reducing flows investigated by the photolithography-electrochemical probes

“…The probe characteristic dimension must be smaller than or equal to the typical size of the large flow structures in order to ensure homogeneity. The electrode size choice has been made accordingly to earlier results obtained in a similar geometry [10] and it will be justified a posteriori.…”

“…However, concerning the transverse velocity component, the results were not so conclusive mostly for methodological reasons: For u x measurements, single electrodes can be used because there is a mean value and though the rms values of the fluctuations may represent about 30% of the average, linear conditions can be approximately fulfilled in the wall region [10].…”

“…It was proved that the z-spectra have similar characteristics as the x ones and that the power of the z-spectra is very small as compared to the x one, which justifies a posteriori to use such an accurate technique [10].…”

Inverse method for the dynamical analysis of wall shear rates using three-segment probes in parallel plate rheometer

“…They permit the measurement of the two shear stress components and of the angle y. The protocol is based on a comparison of the two currents delivered by the two segments of the probe (Deslouis et al, 1993;Py, 1973). However, this kind of probes gives errors when the flow is perpendicular to the isolated gap (Barbeu et al, 1998).…”

Inverse method for electrodiffusional diagnostics of flows

“…In the literature, the most common approaches related to the wall shear stress probes are focused on the research of transfer functions between wall shear stress and limiting diffusion current [6][7][8][9][10][11]. In these works, the axial diffusion mass transfer was neglected and they are generally based on a linearization of the problem by assuming that the wall shear rate fluctuations remain small in comparison with the average value.…”