(g) Circle with a radial fin of finite width, by Eassani. 



(h) Circle with two equal radial fins opposite each other, by J.L. Taylor.^^ Let the 

 greatest width between the outer edges of the fins be n times the diameter of the circle. 

 Then, for motion perpendicular to the plane of the fins, 



«i(V^ 



xAt^T7^r^2" ^^ f^^^ — ^ 



and 



7^1 = - prr (1 + ^2)^2 ^2 



[91g] 



where a is the radius of the circle. 



(i) Broken line, or two plane laminas joined by their edges, by Morton, ^ by Sona, 

 and, with special reference to an airfoil equipped with a rudder, by Sauer, ^^^ who gives 

 other references. Streamlines for the flow without circulation past a right angle, approaching 

 at 15 deg to the plane of one side, are shown in Figure 149. By properly choosing the cir- 

 culation and the direction of approach of the stream, the velocity can be made finite at both 

 edges of the lamina, whatever its angular aperture, as in Figure 150; see Sona.^^^ 



Figure 149 - Flow past a right-angle. 



See Section 91(i). (Copied from 



Reference 106.) 



Figure 150 — Streamlines past an angle-lamina A3, 



with the direction of approach of the stream and 



the circulation around the lamina so chosen 



that the velocity is finite at both edges. 



See Section 91(i). (Copied from 



Reference 115, Lincei 22.) 



224 



