905461.fig.004a
(a)  kHz, side view
905461.fig.004b
(b)  kHz, top view
905461.fig.004c
(c)  kHz, side view
905461.fig.004d
(d)  kHz, top view
Figure 4: Three-dimensional CLEAN-SC [13] sound maps obtained for the nonporous reference airfoil (view from above, flow from left to right,  m/s, PPS 12/2 turbulence grid—position not indicated—mounted directly to the nozzle exit).