shown in Figure 156. Half of S for the case c = 0.94: b is shown by the approximate circle in 

 Figure 154. The streamlines for flow past the limiting form are shown, above the a;-axis only, 

 in Figure 157. If c'^/86^ is rather small, there is an approximation to two circular cylinders 

 in a stream perpendicular to the line joining their centers, which are 26 apart. 



The forces on the two cylinders can be found from the Blasius theorem, as in Section 

 92. The cylinders attract each other, because of higher velocities between them, with a 

 force F = n pfi /{2b ) acting on each. For slender circular cylinders of radius a, 

 F = n pU^ a^/{2b^), approximately. 



A rigid wall may also be inserted along the ;r-axis. Then half of the field represents 

 flow past a cylinder of a certain shape with its axis distant b from a rigid wall. The force 

 F, now directed toward the wall, remains the same. 



(For notation and method; see Section 34; Reference Muller 124.) 



Figure 156 - Two possible forms of the dividing surface S for two 

 equal line dipoles at (0, i 6) in a stream. See Section 93(B). 

 (Copied from Reference 124.) 



231 



