~ "'

Figure 107 Effect of the turbulence level of the inlet stream upon the loss coefficient as a function of the Reynolds number for Ma = 0.5. (From Ref. 242.)

the loss coefficient. The effect of compressibility upon artificial roughening of surfaces is shown in Fig. 109. Comparing Fig. 109a and 109b shows that the reduction of the loss coefficient is effective for the lower range of Reynolds numbers whereas for higher Reynolds numbers, all three surface conditions have similar results. At higher Reynolds numbers, the effect of the additional surface roughness decays faster [263]; therefore, the effect of all three surface conditions is similar.