This paper considers the hydrodynamic performance of a single wave-power device placed at the end of a tapered harbour and set in a reflecting coastline. A relatively simple model, in which the harbour width is assumed to be much smaller than the incident wavelength, is used to calculate approximate values for the hydrodynamic coefficients and hence determine the "energy absorbing capabilities of the device. A comparison is presented between a device in a rectangular harbour and one in a tapered harbour in order to make a preliminary assessment of the influence of the taper.
The design of a wave-power device must inevitably involve a balance between desirable hydrodynamic performance and a number of cost factors, one of the most important of which is construction cost. However, small devices tend to be resonant and possess a narrow bandwidth, so that they only absorb energy efficiently over the band of frequencies close to the single resonant frequency. Thus if financial attractiveness is to be matched by desirable hydrodynamic performance than some improvements to the absorbing properties of the device must be made. To overcome this inherent hydrodynamic difficulty, while maintaining the financial attractiveness of a small device, Ambli et al (1982) proposed the addition of two parallel projecting walls in front of the device to improve hydrodynamic performance. The projecting walls effectively form a rectangular harbour and give rise to additional resonances in the absorber's response to the incoming wave, thus broadening the bandwidth considerably. This concept was incorporated into the design of the shore-mounted prototype Oscillating Water Column (OWC) device installed by Kværner Brug A/S in the coastline near Bergen, Norway. The idea was further developed by a number of authors, particularly by Evans (1983), Evans & McIver (1985), Malmo & Reitan (1986) and McIver & Evans (1988).
