-'-{-€)■ 



[87p] 



Streamlines for the flow past such a parabolic cylinder are shown in Figure 140; only 

 half of the symmetrical plot is shown. The excess of pressure above that at infinity, in 

 steady motion, is also shown a.s p - p^, for points on the cylinder or on the a;-axis ahead of it. 

 This excess is everywhere positive; on the cylinder, it is pU^jS'^/ir, on the a?-axis ahead of it. 



p - p = pU' 



\ \[^ 4a; / ■ 



[87q] 



^^^ 



y 



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--. ~~~~~--^ " 



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— ~~— — .^ ■ — . 



----Zl^^^^[^^~~-~-^^ 



^ ^~~~~~-~~~-^ ~~' — — 



^~"~"~~~~^--~i^^^r"~"\r^~~~ 



^^^^- 



^^""^~~"^^^r^~"~~^^^^^ 



1-^=^ ~— — 



^^^^\^^\ 



/^ ^'-^^^ 



^\y 



^ ^-- rr—- 



__JZI^^-^ 



.| ^— - 



\ 







p^ Plane of Symmetry 

 T 



Figure 140 — Flow past a parabolic cylinder. 



All such flow nets are similar, differing only in scale or in position; for, if /3 is 

 changed, it is only necessary to change x, y, to, <^ and in proportion to j8^ in order to have 

 all equations satisfied. 



(For notation and method; see Section 34.) 



}. THE CIRCULAR-ARC TRANSFORMATION 



Equation [78a] of Section 78 invites generalization as follows: 



'/ - nc / z - c \ '^ 

 '/ + nc \ z + c } 



[88a] 



210 



