144. AXISYMMETRIC JETS 



A few cases of axisymmetric jets have been worked out by elaborate methods of approx- 

 imation. A weai<ly contracting jet was treated by Reissner. 



Schack studied a round jet falling normally upon a plate; his plot of the flow net, 

 labeled in terms of the older convention as to the signs of the velocity potential qS and the 

 stream function 0, is reproduced in Figure 241. The figure shows half of a plane through the 

 axis OD of the jet; the plate lies along OA produced both ways. 



A jet issuing through a round hole in the infinite plane bottom of a tank, under the in- 

 fluence of internal pressure but not of gravity, was studied by Trefftz.^^^ His plot of the 

 flow net is reproduced in Figure 242; it also is labeled in terms of the older convention as to 

 the signs of <t> and 4i. The axis of the hole lies along the vertical line at A. 





1/16 

 



1/4 

 1/8 lA 



3/ 



4 



V 





.25 



sl 











+2.00 











1 







i\)- 





+ 1.75 











1 











+ 1.50 











1 







2U- 





+ 1.25 











1 











+ 1.00 











1 





- 







+0.75 



— 







1 



1 — r 



+ 0.50 







<^{S) = - 3,031 



Figure 241 - Some streamlines and traces of equipotential surfaces, in a plane through 



the axis OD, for a round jet of fluid striking a rigid plate OA. The surface df the 



fluid is at CB. See Section 144. (Copied from Reference 237.) 



S7i 



