Transport Phenomena in Wall Turbulence - Transport and Coherent Structures in Wall Turbulence - page 93

2.9.1. Wall pressure

Figure 2.14, adapted from [TSU 07], recaps the
distribution of the quadratic mean value of the pressure at
the wall as a function of the Reynolds number, obtained by
various authors using measurements and direct numerical
simulations. The size of the wall pressure probes inevitably
affects the resolution. In Figure 2.16, adapted from the
recent study conducted by Tsuji et al. [TSU 07], we show the
distribution of the intensity of the pressure fluctuations,
plotted against the wall friction as a function of d + for the
small range of Reynolds numbers based on the momentum
thickness . We can see a sharp and

continuous decrease in the pressure fluctuations with
sensors whose size is greater than the thickness of the
viscous sublayer. This decrease is clearly due to an effect of
spatial averaging of the active and passive structures in the
inner sublayer. Readers interested in these aspects and the
development of pressure microsensors can consult
[TAR 10b]. Only the measurements obtained with probes
whose size d + <

3 3

4.10 ≤ Re ≤ 5.10

θ

30 are shown in Figure 2.14.

Figure 2.14. Quadratic mean value of the pressure at the wall
in inner variables as a function of the Reynolds number