Studies on the Motion of Viscous Flows— III 

 Because the drag due to the potential flow is zero, we may write Eq. (1.90) as 



^D = I ( ~ Pi ^°^ '^ ~ ^rr ^°^ ^ "•" °'t9 sin i9 j 69 ; _■ 



\- ' /r=l 



+ I I — Pt cos - ct,, cos 6' + o-,fl sin i9 ) dd + • • • , 



J V 9 2 rr^ r^^ I 







where the first integral represents the drag contribution from the first itera- 

 tion and the second integral represents that from the second iteration. 



555 



