Research on Attenuator Type OWC Wave Power Absorber (2nd Report)

It can be said that the mechanism and the characteristics of wave energy absorption of attenuator type devices have not yet been clarified experimentally and theoretically. Therefore, the authors deal with an attenuator type device which consists of five air chambers with and without a bottom plate. In the last report, the authors whowed a part of results of series of experiments in transient waves and the values of numerical result of the strip method, and gave following two conclusion (1) Taking into account the bottom plate on the device, the maximum coefficient of wave energy absorption became large and moved to low frequency range. (2) Without coupling terms between the device and OWC in strip method, the motion of device could be estimated well but the coefficient of wave energy absorption of each OWC could not be estimated well.This paper presents the mathematical model using the 3-D source distribution method and the limitation of successful application of the strip method considering the coupling hydrodynamic forces by means of comparison between the experimental results and the calculated results. From these results, this paper shows the characteristics of wave energy absorption of the device in the head and oblique sea condition, and shows the effect of the bottom plate for the wave energy absorption and the reason of its improvement.