Measurements of the three fluctuating components of the velocity and of the two components of the wall shear stress fluctuations have been made in a fully developed turbulent channel flow at Re=7700 using hot-film probes. These measurements include rms values, skewness and flatness factors, and probability density functions. Although the wall region is emphasized here, information for the whole channel half-width is also given.

The fluctuating velocity components, u and w, and their gradients at the wall, \[ (\partial u/\partial y)|_{w}\quad {\rm and}\quad (\partial w/\partial y)|_{w}, \] were measured in a fully developed turbulent channel flow using hot-film probes. The data were taken in an oil channel at a low Reynolds number which allowed velocity measurements very close to the wall. From simultaneous measurements of these signals it could be deduced that coherent flow structures, inclined to the wall, travel downstream. Space-time correlations imply that these are rotating structures. The spanwise distance between these structures was found to be z+ ≈ 50 and they could be observed over a streamwise distance of Δx+ > 1000.

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