A • TRANSITION FROM LAMINAR TO TURBULENT FLOW 



X 



16 



12 



q:: 8 



0) 



•+- 

 o 



i 4 



o 



a 

 a 



< 



20 



30 



40 



50 



60 



ReX 10 



-6 



Fig. A, 17b. Approximate transition Reynolds number (equivalent flat plate 

 value) for airfoil boundary layers as function of airfoil Reynolds number. 



Loftin, rivets spaced 3 in., 

 single row 



Airfoil 1 0.35c o^ 

 0.50c a 



0.65c A 



Rivet 

 diameter 

 0.035 in. 



> Rivet 

 diameter 

 0.015 in, 



Fig. A, 17c. Effect of roughness on transition Reynolds number of airfoils. 



(44 ) 



