*!(s,CH-) - 0(s 2 ) at infinity 



which corresponds to the strong singularity Vifc ■ 0(x 2 ). With that 



choice of E(a) the solution is still not unique, because the wake 



strength A is undetermined. We can argue that conditions are such 



that there should be no Jump in tangential velocity across the extension 



1 1 



of the plate, in which case A - 0, V<|> - 0(x~ T ) and <J> - 0(x 2 ) near the 



plate edge and we have a situation essentially the same as was examined 



in $8. Because the radiation is emitted into uniformly moving fluid 



the "stationary phasfe" formula (8.29) is not immediately applicable, but 



we shall show in a moment how it can be generalized to the moving fluid 



case. 



We can alternatively argue that a wake will adjust itself to 

 eliminate the high velocities which would otherwise exist at the trail- 

 ing edge, and that a Kutta condition of finiteness of the velocities 

 at the edge should be imposed whenever possible. The physical basis 

 for such a condition in unsteady trailing edge flow is a matter of 

 controversy at the moment, but that does not concern us here as our 

 interest is merely in seeing if and how such a condition can be applied 

 in this model problem. 



Expand the© part of (9.18) as s ■*■ « in R + . We have 



/ k ivD(-q) £ (-q)\ 1 I 



♦ • + (..0> - \UXJ- f ) + °^_ q) j (1 + M) 2 a" * 



+ 0(s" T ) (9.19) 



the term given explicitly corresponding to ?if ■ 0(x ) the second *.o 



l 

 V<{> ■ 0(x T ). Thus we can impose a Kutta condition, that the velocities 



67 



