Figure 73 — Streamlines between two nearly 



circular cylinders, mounted in walls or 



forming two members of an infinite 



grating. See Section 46. 



Figure 74 — Row of equal line dipoles 

 with longitudinal axes. 



Uiy-a) =^ sin "" ^ 



[46r] 



Thus, if no walls are inserted, the formulas represent a stream flowing at normal incidence 

 through a grating whose bars are represented by the surfaces S. The bars are nearly circular 

 in section provided their diameters are smaller than the intervening spaces. Some streamlines 

 for this case are shown in Figure 73. 



(For notation and method; see Section 34; Reference 1, Article 64.) 



47. ROW OF EQUAL LINE DIPOLES ON A LONGITUDINAL AXIS; 

 FLOW PAST A GRATING 



w = B cot — , a and B real 



[47a] 



2nx D 2ny 



<;4 =iisin , >// = --S sinh— ^ 



H a H a 



_e 



[47b,c] 



r ^ nx o "y~\ 



H = 2 \ sin^ + sinh'' — = cosh 



La a J 



2ny 2tiX 

 - cos 



[47d] 



112 



