This wave energy converter is formed so as to extract the wave energy through the dynamic systems between the floats and the links and between the adjacent links, and the natural frequency of the float group is approximately tuned to the frequency of the incident wave. 6 shows the energy absorbing efficiency of a 1-float type wave energy converter with one end of the float fixed for instance to a pier or a breakwater, which converter has a dynamic system including a mass means, a restoring means, and a damping means. The maximum efficiency of the curve (5) is restricted to a point P, and the energy absorbing efficiency is rapidly reduced as the frequency of the incident wave deviates from the point P, so that it is very difficult to efficiently extract the wave energy by using a 1-float system with one end of the float being fixed.
Tipos De Dolor De Cabeza
Thus, the 1-float type wave energy converter is not practicable. Kx) travelling leftward satisfy the following equation (11) if the wave energy is not extracted and the following equation (12) if wave energy is extracted. To fulfil the object, the wave energy converter according to the present invention does not use any floats which are fixed to or restricted by the coastal ground or sea bed.
If the wave energy converter of the invention is fixed to a pier or sea bed, the movement of the floats is restricted and its energy absorbing efficiency is greatly reduced, for instance to 10 to 20% of that of non-fixed installations. Relative movements the three floats and the two links were considered while assuming that the float shape and the selection of the coefficient of viscous damping and the distance between the floats was the same as those of the previous 2-float system.
More specifically, the invention relates to a wave energy converter having a group of at least two floats connected by elongated rigid links disposed at a right angle to the direction of incidence of the waves, which floats are free from the coastal ground and sea bed and are allowed to heave, to sway, and to roll, so that a dynamic system is formed to absorb energy from relative movements between the floats and the links and between the adjacent links, while the natural frequency of this system is approximately tuned to the frequency of the incident wave, whereby the energy absorbing efficiency is remarkably increased and the frequency band having a high energy absorbing efficiency is widened.
FIGS. 3A, 3B, 3C(A) and 3C(B) illustrate one example of a mechanism to convert the aforesaid relative movements due to the wave energy into a one-way air flow to drive an air turbine 11, the rotation of the air turbine being transmitted to an electric generator 12 for producing electric energy. 2 e-i2Kl, and Xj R and Xj L are j mode complex amplitudes for the floats R and L. The following equation representing the motion of the 2-float system can be derived by considering the coercions by links, added mass forces, damping forces, static restoring forces, and resistive forces due to the damping means in response to the waves. This is due to the fact that the energy absorbing efficiency curve of the Bessho system has a comparatively sharp peak at the tuned frequency of the incident wave.
In view of the severe conditions of the open sea, the floats are preferably hermetically sealed, so that the floats are prevented from sinking in high waves during a typhoon, because the sinking may leads to breakdown of the floats. Accordingly, it is apparent that the Bessho system necessitates preparation of a plurality of float systems with different natural frequencies so as to facilitate interchange of the float systems when the meterological conditions are changed. The curve (3) shows that the maximum energy absorbing efficiency is close to 0.99, which means that almost all of the incident wave energy is extracted by the converter. 6, the values of l’ and μ0 ‘ were selected so as to obtain maximum efficiency at the prescribed dimensionless angular frequency ω2 D/g by a computer. In FIG. 6, C1 ‘, l2 ‘, l’, μ0 ‘ are dimensionless values obtained by dividing the quantities C1, l2, l (FIG.
5), and μ0 by B. Dolor muscular o de riñon . In calculating the curves of FIG. Theoretically, the Bessho system is advantageous in that when the natural frequency of the fluid-float system is tuned to the major frequency of the incident wave, the entire energy carried by the incident wave can be extracted from the motions such as heaving, swaying, and rolling of the float relative to the fixed point to which the float is secured through the aforesaid dynamic system (including the damping mechanism, the restoring mechanism, and the mass mechanism), and that the reflected waves and the transmitted waves from the float can be suppressed substantially to zero. 1. One end of a float A disposed on the sea is connected to a fixed point G, such as the coastal ground or sea bed, through a dynamic system B. The dynamic system B comprises a mass means E having one end thereof connected to the float A, a restoring means C disposed between the opposite end of the mass means E and the fixed portion G, and a damping means D connected in parallel with the restoring means C. This construction of the prior art has shortcomings in the susceptibleness to excessive displacements at high seas or the like and in the narrowness of the tuning of the natural frequency thereof to that of the incident waves.
Dolor Neuropático Central
6 for the present invention and the curve (5) thereof for the prior art based on numerical calculations by using theoretically derived equations. Most systems of the prior art to extract ocean wave energy use floats which heave and roll in response to the motion of the incident wave, so that the systems extract wave energy by using the movement of the floats relative to fixed ends thereof secured to coastal ground or the sea bed. When the aforesaid tuning is established, the reflected waves and the transmitted waves produced by the float are minimized substantially to zero, so that the entire energy carried by the incident wave can be extracted.
In the sea surrounding Japan, the average energy carried by wave of a wave height H and a wave period T is given by H2 T/2.3 kW/m, so that in the sea where the wave height is B 2 m and wave period is 6 sec., the average wave energy is 10 kW/m. Consequently, the float produces two kinds of waves on the surrounding water surfaces; namely, a scattered wave and a radiated wave. If the distance l between the two floats is long enough as compared with the distance which is subjected to the influence of the local wave produced by the movement of the float, such waves can be determined by considering the travelling wave components only.
Dolores Musculares Piernas
3) Considerable wave suppressing effect can be achieved at the back of the float group by using this system. A float floating on the sea is secured to the coastal ground or sea bed through a dynamic system including a restoring mechanism, damping mechanism, and a mass mechanism. FIG. 2B shows another model of the invention, which uses three floats connected in a linear fashion by two links 2. Each of the joints between the float 1 and the link 2 is provided with a restoring means 3 and a damping means 4, so as to form a dynamic system 5A there. When a wave energy converter of the invention is formed by using two, three or four of the aforesaid floats connected by links so as to extend over a span of about 100 m, if the energy absorbing efficiency of the converter is 90% as explained above, about 900 kW of mechanical power can be extracted from the wave.
Salient features of the wave energy converter of the invention can be summarized as follows. This invention relates to a wave energy converter suitable for absorbing ocean wave energy. 6 for different frequencies of the incident wave, which variations indicate the manner in which the wave energy is effectively absorbed by the converter of the present invention. Dolor parte superior de la espalda . In this way, practically the entire energy of the incident wave is extracted, and the reflected waves and the transmitted waves caused by the floats are minimized substantially to zero. 6 shows the energy absorbing efficiency of the 3-float system using the floats whose shapes are the same as those of the 2-float system of the curve (1) of the figure.
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For example, when 50 sets of such wave energy converters are disposed on the sea, about 45,000 kW of mechanical power can be extracted from the wave energy. The swaying x(t), the heaving y(t), and the rolling θ(t) of the float can be expressed as follows. Throughout different views of the drawing, 1 is a float, 2 is a link, 3 is a restoring means, 4 is a damping means, 5 is an air chamber, 6 is a rotary blade, 7, 8 are intake ports, 7A through 7D are intake valves, 8A through 8D are discharge valves, 9, 10 are discharge passages, 11 is an air turbine, 12 is an electric generator, 13 is an air accumulator, 14 is a flow rate control valve, and 15 is a relief valve.