598 



In llie boundarj' layer defined by 0<^y<^D„, the value of 

 — uv is found to be : 



- rdD Cy\ rdD f\-y\ 1 

 A i-v 



280 J i? '^' \d) 



(0+K£ 



1/ 

 1 



(41) 



280 



70(J.Y-21!4(A)'+.8«('A|_,6„, 



Using the formulae (40) and (41) we find : 

 1 







1 



-ƒ' 



jdy(uvy = (^^^{\-\M^D,) 







and by means of the latter there results: 



T=: 0,710 I>„ — (42) 



The value of x can be calculated in the following way : The 

 vortices having thicknesses between the limits D and D-\-dD 



contribute to the integral — idy uv the amount: 



DJ \D) 315 







hence, according to (30), to the integral I dy i' : 



294 dD 

 315 15^ 

 To this must be added the contribution of the vortices with 

 thickness 1, amounting to: 



in 



294 



hence in 



C - 1 



— I dij uv : — — ; 

 J ^ 2520 



2520 

 Adding all parts together, we get: 



/• _ 294 / 1 \ 294 294 / 1 7\ 



