﻿452 Mr. G. B. Jeffery on the 



Thus it will be seen that although the general formula. 1 

 are somewhat complex, yet when we apply them to particular 

 sets of coordinates they become in many cases comparatively 

 simple. 



§ 3. Axial Motion. 



The case in which we have symmetry of motion about an 

 axis can be discussed by means of the equations in cylin- 

 drical coordinates. We w T ill suppose the fluid to be incom- 

 pressible and the external forces to be derivable from a 

 potential V. Then writing 



and puttin o-^— = the equations in cylindrical coordinates 

 ov 



become 





"-- = |*^( V ,,_Ji\ . . . (11) 



t -37 $■&■ \ 'US') 



where 



S = §f^VS (13) 



® _ b , a b 



The equation ol continuity is 

 and hence 



i a-f 1 <u- 



even if there is a velocity component perpendicular to the? 

 meridian plane. 



Equation (12) becomes 



o 



l ~b<r d r , 1 d^dv i Bi/r / »\ 



t VT QZ O^T -st 0^7 o~ ^" <K V & / 



Let «ro = H 



