Scaling of the bursting frequency in turbulent boundary layers

The bursting frequency in turbulent boundary layers has been measured over the Reynolds-number range 10 3 < U ∞ /ν < 10 4 . When scaled with the variables appropriate for the wall region, the non-dimensional frequency was constant independent of Reynolds number. A strong effect of the sensor size was noted on the measured bursting frequency. Only sensors having a spatial scale less than twenty viscous lengthscales were free from spatial-averaging effects and yielded consistent results. The spatial-resolution problem was apparently the reason for erroneous results reported in the past.