Tapered Channel Wave Energy

Results

Five trials testing the model were conducted. Each trial varied the width of the channel opening. The experiment yielded the following results:
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Ho is the measured minimum wave height necessary for the wave to be able to splash into the resevoir. D2 is the width of the channel opening at the bottom of the ramp. Throughout the experiment, all other variables including the width of the channel opening at the top of the ramp, the reservoir height, and the wave generating method remained constant.

Analysis

There are two main factors which affect the minimum wave height for waves to reach the reservoir. Both factors are dependent on D2.

1. Concentration of Wave Energy
The idea behing tapered channel wave power is that by "collecting" waves into a tapered channel, the energy of the waves will become more concentrated. As the channel tapers, the water will have the same amount of energy as before, but it will be concentrated into a smaller area. As a consequence of this, the waves will increase in height.
The following equation governs the energy of water waves:
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This equation implies that as the area decreases, the wave height will increase. So, in using the tapered channel, wave height will increase as the width of the channel decreases.

2. Reflection of Wave Energy
One characteristic of waves is that they reflect off of certain surfaces. Water waves reflect the most completely off of hard surfaces. In the case of the tapered channel, some of the energy carried by the wave will reflect off the ramp or channel sides. Reflected wave energy may be considered as wave energy lost to the purpose of collecting waves in the reservoir. A channel with no taper will have minimal energy lost to wave reflection because waves are travelling perpendicular to the channel sides. As the angle of taper increases, more wave energy is lost to reflection. This concept implies that for the particular model tested, as D2 increased, the amount of wave energy lost to reflection increased.
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