Wave Motion due to a Submerged Obstacle. 5382 
9. With (63) and (64) we can now calculate the resistance R from (58). 
For a given depth f, the variation of the resistance with the velocity is shown 
in the following curve, for which R has been calculated for various values of 
e]/ (Gf). 
Se fe (Oi mo ere eee | ED 
SH - ; 
The curve is very similar in form to the two-dimensional case of a circular 
cylinder. For small velocities, that is « large, if we take the first term of the 
asymptotic expansion (64), we have 
R = yf (21°97) f) . paSc Se 2a, 
which may be compared with (30) for the cylinder. It is of interest to 
notice the similar law of variation of wave resistance with speed for the few 
cases of rigid bodies which have been worked out. The method adopted here 
can be applied to bodies of different forms, and it is hoped to illustrate later 
some interference effects. 
