FIG. IA 



Z- PLANE 



RE-ENTRANT JET CAVITY 



S- PLANE 



FIG IC 



FIG. IB 



A more precise estimate is 



CdW) 



4 + 7T 



1 + C7 + 



»(t + 4) _ 



(7) 



The formula (6) underestimates within .8 percent at a — 1 and improves in accuracy 



as a -> 0. If the flat plate is replaced by a symmetric wedge of semiangle air the 



1 

 exponent — in (3) and (5) is replaced by a. 



In asymmetric flow without circulation past an arbitrary obstacle of diameter /, 

 the drag and lift coefficients are related to the jet width / and direction y by the 

 formulas 



J , , 2J 



C D ( a ) = 2 - V 1 + a (1 - V 1 + o- cos 7), ClW) = sin 7. (8) 



I I 



283 



