In the previous paper, we have proposed a new type of wave-energy converter using an unbalanced rotor. A rotor with a large unbalanced mass which is applied an oscillating motion, can be kept in rotation like a hula-hoop. A power generator is connected to the unbalanced rotor by an over drive gear. In this paper, to clarify the fundamental characteristics of the new wave-energy converter simple mechanical models are analyzed theoretically and numerically. Actual size numerical models are analyzed to obtain the capability of energy conversion and to design the rotation stabilizer.
Recently, there have been conducted a lot of investigations on alternative renewable source of energy. One possible source of renewable energy is contained in the ocean wave. The wave-energy is clean, safe, and permanent. The essential problem is finding a method to convert dispersed, random, and alternating forces into concentrated, direct forces. Many promising ideas for the wave-energy converting device have been suggested, and a number of theoretical and experimental studies have been carried on. For example, "Salter's Duck" in which the duck shaped cylinders role to match the motion of the water particles and drive spline-pumps, was devised by (Salter, 1974). "Oscillating water column" was invented and tested by (Masuda, 1979) and has been used to provide power for beacons or small lighthouses. Wave cause the water column in air chamber of a buoy to oscillate. This, in turn, causes entering and leaving airflow to drive an air turbine. The International Energy Agency and the Japan Marine Science and Technology Center have been testing "KAIMEI" the largest wave-power generator ship, for years (Ohno,1980). Kawatani (1986) studied experimentally the two floating-body-type wave-energy converting system. The authors (Araki, 1987 a, b) have proposed a new type of wave-energy converter using an unbalanced rotor.