CALCULATIONS ILLUSTRATING THE EFFECT OF BOUNDARY LAYER ON WAVE RESISTANCE 
Re _ 2 
Re fa — emi + cos 2 
2 
—-sin2 y+ —(1 — cos2 | cost aa . (26 
7 Y > y) (26) 
with 
= gI|v*; By = g dfv?; y = yosec 0; B = By sec? 0 
Tn this, and similar integrals, it has been found more 
convenient for computation to change the variable from 
@ to u given by cos @=sechwu. The integral was then 
evaluated by direct quadrature, together with an asymp- 
totic expansion for low speeds when the parameter yo is 
large. The curve is shown as D in Fig: 2. 
035 
030 
. O25 
wale 
2 020 
WwW 
O 
eg OAS 
aa) 
S 
” OO 
SCALE oF -f 
Fic. 2 
We shall not use the same modifications as in the 
previous section, simply because the cubic curve adds so 
much to the numerical work. It is sufficient for the 
present to assume a simple parabolic curve 
N=4+aé+a,2 . . . (27) 
for the new part of the streamline near the stern. First 
we suppose the curve leaves the form tangentially at 
1 ft. before the stern and becomes parallel to the central 
line at 1 ft. to the rear, assuming a model length of 16 ft. 
Hence the conditions are 
15 dn 7 7 
GB aie ae ES Sr 
(28) 
BN Vion oe 
dé 2 org =—% 
These give the curve 
10 63 
= Wer le fo se eo(29) 
which is shown starting from the point E of the section 
in Fig. 2. It passes the stern at a transverse distance 
9 5/128 and it finishes at a transverse distance b/64. We 
have now 
1 ae 
I+iJ= ~2|eercars (Bs re)erae 
-4 —3 
(30) 
