All-101 92 



If boundary conditions are imposed and if t and t 



y ^ 



are specified, the problem defined by (10) can be solved (see 

 Appendix 5). Thus for the analysis of the steady state prob- 

 lem, the only necessary assumption concerning the pressure and 

 the density is that the density be constant along the surface 

 below which the velocities are negligible. 



If the height z = -h is approximated by a constant, 

 then the derivatives of the pressure terms in (9) vanish and 

 no assumption need be made concerning the density along the 

 surface z = -h. 



