seen that increasing the draft depth of the chamber will lead to a significant decline
in the performance of the system in the short period, while increasing the optimal
response period. This is easy to understand, because increasing the draft depth of
the chamber increases the length of the oscillating water column, which increases
the inertia of the system. The greater the inertia of the system, the worse the
response to the high-frequency input, so the worse the performance in the short
period. At the same time, increasing the inertia of the system makes the natural
frequency of the system decrease, so the resonance frequency decreases. Therefore,
increasing the draft depth of the chamber will increase the optimal response period.
The purpose of the comparative test of different draft depths of air chambers is to
study the influence of different air chamber heights. Because the total length of the
central tube is constant during the test, the test results actually reflect the influence
Fig. 14.12 Variation of air
chamber characteristics with
nozzle ratio
Fig. 14.13 Variation of air
chamber performance with
draft depth
14.4 Experimental Technique of Oscillatory Water Column Wave Energy Converter
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