A,5 • SURFACE ROUGHNESS AND WAVINESS 

 1.6 



1.2 



X 



0.8 



0.4 



0.2 



0.4 0.6 



0.8 



1.0 



Fig. A,5e. Effect of single cylindrical roughness element on the transition 

 Reynolds number of a plate. Measurements of Stiiper [19]. 



2.2 



X 



(U 



1.4 



1.0 



20 mm ridge 



50 cm from leading edge 



k varied 



k/5,* 



Fig. A,5f. Effect of single flat-ridge roughness element on the transition 

 Reynolds number of a plate. Measurements of Scherbarth [20]. 



is relatively less sensitive to roughness at high turbulence levels. How- 

 ever, the change in /c/5| for a reduction of the transition Reynolds num- 

 ber to one half its original value is only from 0.47 to 0.66. Curves are 

 drawn for several turbulence levels; they are applicable only to single 

 roughness elements in the form of cyhndrical wires and flat ridges for 



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