Figure 91 - Streamlines due to a line vortex at P, opposite a semi-infinite 

 rigid plane extending from toward the right. 



Figure 92 - The vortex of Figure 91 before 

 transformation to the 2-plane. 



TRANSFORMATIONS DEFINED INVERSELY 



61. ELLIPSES AND HYPERBOLAS 



z = c cosh w 

 Here c is a real positive coastant. Since z=x + iy,w=4'+ iip, 



136 



[61a] 



