(a) Mean flow velocity

(b) Root-mean-square of the turbulent velocity fluctuations

(c) according to(6)

Figure 8: Parameters of the turbulent inflow, measured in a plane 7 mm upstream of the leading edge of the nonporous reference airfoil, as a function of the nominal flow speed (turbulence grids: (blue—dash) PPS 12/2, (red—dash) PPS 14/4), solid lines: airfoil leading edge at  m (distance to turbulence grid 0.1 m), dashed line:  m (0.2 m), dotted line:  m (0.3 m).