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CHAPTER 7. LABORATORY WAVE GENERATION
Figure 7.4: Maximum Capability of a Piston-Type Wavemaker.
cm (9.8 in). The linear theory wavelength is calculated to be L = 300 cm (118 in),
and the fresh water in the wave flume has a specific weight of pg = 9.8 kN/m3 (62.4
lb/ft3). Compare wave board stroke and mean power requirements for a piston-type
and a flap-type wavemaker.
Piston-Type Wavemaker. First calculate the relative depth as
2irh
2ir(25 cm)
L
300 cm
0.524
From Eqn. 7.58 the wave height-to-stroke ratio for a piston-type wavemaker is
H _
4sinh2jth
_
4sinh2(0.524)
1.201
So ~ sinh 2kh + 2kh ~ sinh 2(0.524) + 2(0.524) “ 2.297
and the required piston stroke at z = 0 is
So
H
0.523
6 cm
z. _ • ■<
——— = 11.5 cm (4.5 tn)
0.523
------------v
’
The required mean power to generate this wave with a piston-type wavemaker is
found from Eqn. 7.82 with I —► oo, or