Page 194 - Introduction to Naval Architecture
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180 RESISTANCE
Figure 8.2 Pressure point wave system
of the divergent waves to the centreline will not be exactly that of the
Kelvin wave field. The maximum crest heights of the divergent waves do
lie on a line at an angle to the centreline and the local crests at the
maxima are at about twice this angle to the centreline. The stern
generated waves are less clear, pardy because they are weaker, but mainly
because of the interference they suffer from the bow system.
Interference effects
In addition to the waves created by the bow and stern others may be
created by local discontinuities along the ship's length. However the
qualitative nature of the interference effects in wave-making resistance
are illustrated by considering just the bow and stern systems. The
transverse waves from the bow travel aft relative to the ship, reducing in
height. When they reach the stern-generated waves they interact with
them. If crests of the two systems coincide the resulting wave is of
greater magnitude than either because their energies combine. If the
crest of one coincides with a trough in the other the resultant energy
Figure 8.3 Bow and stern wave systems
