Showing papers on "Wave power published in 1982"

Wave power conversion by point absorbers - A Norwegian project

Abstract: SYNOPSIS This paper describes a spherical buoy, which can perform heaving oscillation relative to a strut joined to an anchor on the sea bed. The buoy is supplied with latching means for optimum phase control and with an air turbine for power take-off. The electrical generator is rated at 0.4 MW. An estimate is given for the cost of a 200 MW power plant and for its annual energy production if placed off the west coast of Norway. The estimated electricity cost is approximately 4 p/kWh. At the present stage of the research, it is consequently not competitive with hydroelectric power plants in Norway. However. There are several options for cost reduction of a powerbuoy plant.

Resonant wave acceleration of minor ions in the solar wind

Abstract: This paper extends some previous work on the acceleration of minor ions in the solar wind to include the effects of wave acceleration and heating arising from minor ions interacting via the gyroresonance with ion cyclotron waves. Resonant wave acceleration is made up of two contributions, the first, and generally the more important, is a ‘local’ acceleration which is proportional to the wave power and the number of resonant particles and is also sensitive to the details of the distribution function; while the other contribution is basically ‘fluid dynamic’ in character, arises from the inhomogeneity of the medium and is proportional to the radial gradient of the resonant wave power. Under suitable cir-cumstances both contributions exhibit the feature that heavier ions receive greater acceleration than lighter ones. Also the kinematics of the resonance shows that the resonance wave acceleration switches off above a maximum differential speed, between ions and protons, which increases with increasing ratio of mass to charge. We also examine briefly possible beam instabilities driven by the streaming of minor ions relative to protons.

A Monte Carlo approach to the computation of refraction of water waves

Abstract: The equations describing refraction of water waves are based on the geometrical optics approximation, in which wave rays are calculated independently of each other. For this reason the model reacts sensitively to small variations in depth as well as in incident wave frequency and direction. This leads to an uncertainty in the interpretation of the location of individual rays, particularly in cases of large travel distances through regions with weakly irregular bottom topography, as in shelf seas. In this paper, this uncertainty is taken into account from the outset by treating the results of the ray calculations as a case of statistical sampling, in which a tradeoff is made between resolution and confidence. To this end, the area being studied is divided into a number of subregions (bins), in each of which the total wave energy is estimated from the rays passing through it, each ray being considered as a carrier of a certain amount of wave power. The size of the bins determines the spatial resolution. It must be chosen in conjunction with the discretization intervals for ray separation, frequency, and direction, considering also the propagation distance, the length scale of the target area, and the bottom topography. This is illustrated with an example from JONSWAP.

Wave-power generating plant

Abstract: In said plant, retaining cables that are secured to a support device, constructed underwater, or on an underwater machine shop, are used to retain a hollow body in such a way that the latter can roll freely on the waves of the sea, and its upward movements are led by means of tension cables to units, located underwater, for dynamos for the generation of power, which movements cause the units to rotate (Fig. 1). When the hollow body descends, the tension cables are rewound tightly during idling onto their cable drums by counterweights. Since the hollow body which develops the power for generating current is supported by the water, it can, within the bounds of technical feasibility, be constructed with large dimensions, for example the size of a football pitch. In this case, the guying, the number and strength of the retaining cables, and of the tension cables, as well, must be appropriate for the purpose of withstanding bad weather, as well. The power generation is extremely low on occasions, and then once again extremely high, and can be led into the public power grid only given special precautions.

Power flow and energy distribution of magnetostatic bulk and surface waves in dielectric layered structure

Abstract: A theoretical study of power flow and energy distribution of guided magnetostatic surface and bulk waves in a dielectric layered structure consisting of a ferrimagnetic layer sandwiched between free space and grounded dielectric has been presented. Starting from generalized Poynting theorem for dispersive media, the expressions for power flow per unit area and energy density have been derived under the magnetostatic approximation. The velocity of energy flow has been shown to be equal to group velocity, which implies the consistency of the magnetostatic approximation with general principle of wave propagation. The analysis reveals that the power flow in air or dielectric regions occurs in a direction opposite to that of phase propagation, while, inside ferrimagnetic region, the magnetostatic wave power usually flows along or opposite to that of phase propagation depending on whether the wave in question is a forward or backward wave. The region of non-dispersive delay, obtained exclusively for forward waves, is identified with the sharp decrease in the magnitude of power in ferrimagnetic and dielectric regions, immediately after the peaks have been obtained. No such behaviour is obtained for backward waves.

Wave power generating plant

Abstract: PURPOSE:To take out the wave energy efficiently by using a piston-cylinder type pupmp to be operated by a float body for pumping up water and operating a generator by the head pressure of the pumped up water CONSTITUTION:A piston 9 in a piston-cylinder unit 7 is always given a downward force on the basis of te difference between a water head pressure given to a suction port 13, that is, the water head pressure by the water face in a lower reservoir 4 and a water head pressure given to a regulation chamber 12, that is, the water head pressure by the water face in a regulation tank 19, and a cable 6 is kept in a tense state Consequently, a float body 5 connected to the cable 6 is vartically moved to operate the piston 9, and the water in an upper reservoir 1 is made to flow down to operate a generator 3

Device for obtaining compressed air for generation of electricity from wave power

Abstract: PURPOSE:To obtain power for generation of electricity by permitting a metallic block in a cylinder to be moved by impulsive force of wave power. CONSTITUTION:An outer case 4 taking plurality of connected catamaran shaped floating bodies as a fundamental form is inclined in its both ends and its lower end is formed into an acute angle. An ellipsoidal cylinder 1 is formed on the central part of these floating bodies, and a metallic block 2 acting as a piston movable to the right and left, an air intake-exhaust port 3 at the right and left of the cylinder 1 and a spring 6 for moderating impulsive force of the metallic block 2 are provided inside said cylinder 1. The metallic block 2 is moved to the right and left by the impulsive force of wave power such as that of seawater put in a floating body outer case 4, and thereby compressed air is produced in the cylinder 1. This compressed air is utilized for power for generation of electricity.

Wave power generating method and device

Abstract: PURPOSE: To remove the periodical fluctuation of a wave power generating output which is based on the periodical property of the energy of wave power by a method wherein a hydraulic motor is connected with an accumulator. CONSTITUTION: In case a pendulum 107 is swung by the wave power and a cylinder 110 is being driven, oil discharged out of the cylinder 110 flows to the hydraulic motor 121a and the accumulator 125a simultaneously when a piston 110a is being shifted to the left. When the piston 110a is moved to the right, the discharged oil from the cylinder 110 flows to the hydraulic motor 121b and the accumulator 125b. Accordingly, a generator is driven for this period by the hydraulic motor 121b instead of the same 121a, however, the hydraulic motor 121a drives the generator successively for a period of time in which the oil in the accumulator 125a is being discharged. COPYRIGHT: (C)1983,JPO&Japio

Fundamental Research on Absorbing Energy from Ocean Waves (1 st report)

Abstract: Characteristics of a fixed terminator of oscillating water column are described in this paper. It is one of the most promising wave power absorbers, as well as a floating-body-type such as Salters Duck, performances of which were shown in the previous papers. The experimental data both in regular and in irregular waves are compared with calculations based on a linear water wave theory with equivalent floating body approximation. The calculations agree very well with experiments in case of deep water depth and low frequencies. The ability to absorb wave energy is as excellent as Salters Duck both in regular and in irregular waves.

Calculation of Trapped Reflective Wave

Abstract: An increase in reflected wave energy may result where structures are built along a section of coastline with no beach fronting the structure. In certain instances the structures may combine with a steep bottom slope to form a wave guide which can trap wave energy, magnify wave heights, and increase erosion along an adjacent section of shoreline. Calculations are presented to determine the effects of such trapped wave energy.

Storm directional wave spectra measured with a single buoy

Abstract: The Endeco 956 Wavetrack Buoy was one of many wave sensors involved in the ARSLOE experiment in the Fall of 1980. Since that time, a new signal processing approach has been developed to produce directional wave spectra for comparison with all other sensors used in the experiment. The authors are under contract to NOAA Coastal Waves Program group and have been concerned with minimizing the limitations of a single buoy method for obtaining directional spectral results. The previous results of the development have been briefly reported in the Oceans '81 meeting in Boston, the Berkeley meeting, the Paris meeting, as well as in workshops called for all participants of the ARSLOE experiment. The purpose of the present paper is to discuss certain refinements to the method of analysis that improved directional resolution, and improved the ease of interpretation of processed wave data. One example of this improvement resulted from the application of a special "window or weighting function" which eliminated an analysis related artifact which appeared as a backward-traveling wave component. The paper presents the directional spectra for different time intervals through the growth and decay of a storm. These are in the form of contours of constant wave power on a direction (magnetic) vs frequency cartesian plane.

Wave power generating method

Abstract: PURPOSE:To cause an air stream from a wave in a ventilation pipe and use the air stream for power generation, by arranging a pair of or plural pairs of flexible air chambers to the forward direction of the wave under the level of water at a distance in integral multiplex of half wave length and communicating the air chambers of each pair through the ventilation pipe. CONSTITUTION:An example of arranging a pair of flexible air chambers 1, 2 is shown in the drawing, in which the chambers are arranged with a distance of half wave L/2 of the wave length L and communicated by a ventilation pipe 5. The numeral 6 is a generator chamber in which a one-way commutating valve and air turbine are assembled. When a wave is positioned as shown in the drawing, a crest of the wave is located above the air chamber 1, then the air chamber 1 is applied with a water head larger than a water head applied to the air chamber 2 located below a trough of the wave, and the air chamber 1 is compressed as shown by a full line, reversely the air chamber 2 is inflated, then air in the ventilation pipe flows to the direction of an arrow head, if the wave is reversely positioned, the air flows to the direction of an inverse arrow head, in this way, movement of the air stream is utilized to perform electric power generation.

Water power generation system in which pressure is applied to water using wave power to pump up water by use of pressure and wave power for generating electricity

Abstract: PURPOSE:To make petroleum useless as energy for power generation by generating electricity by applying pressure to water using wave power to pump up water to a height by said pressure and wave power CONSTITUTION:Water, etc, are made to be a medium of force by wave power, and pressure is given to the water using a pump, etc Further, the water is pumped up to a height by wave power using a pump, and thereby potential energy and energy by pressure of water are utilized for generating electricity

Method of producing liquefied air by wave power

Abstract: PURPOSE:To effectively utilize the energy of waves, by providing an air compressor on a platform supported on the sea by a submerged base, and by using the vertical moving force of a float due to the wave power to actuate the cylinder of the air compressor to obtain liquefied air. CONSTITUTION:An air compressor 4 is installed on a platform 3 supported on the sea by a submerged base 1. A float 7 is attached to the air compressor 4 through an operating rod 6. The cylinder of the air compressor 4 is actuated by the vertical moving force of the float 7 due to wave power to compress air. After the compressed air is cooled, it is adiabatically expanded so that it is liquefied. Since the liquefied air which is a nonpollutive portable energy source is producted by the wave energy, the wave energy can be effectively utilized.

On the possibility of extracting power from resonant harbour oscillations

Abstract: In this paper the authors examine the possibility of extracting wave power using energy-capturing devices placed inside specially shaped artificial basins, rather than with offshore free-floating installations.

Wave power generater

Abstract: PURPOSE:To improve the efficiency, using only rolling-in waves while excluding rolling-back waves. CONSTITUTION:Supports 3 are provided to groundworks 1 formed in the sea bed, and have slopes 5, 5' having guides 4 and stepped spaces 7. Waves move up the slopes 5, enter wave receivers 8, 9 and fall through a fall passage 10 to rotate a water mill 11. The water that has not entered the wave receivers rolls back, and falls through the stepped spaces 7 not to weaken the force of the rolling-up waves.

Wave energy absorbing device

Abstract: PURPOSE:To both efficiently absorb energy and reduce horizontal force to a dolphin affected by a float in a wave energy absorbing device constituted by coupling the float to the dolphin, by applying the specific flat submerged float. CONSTITUTION:A flat submerged float 1, consisting of mutually separated two exposed parts 1a above a surface of water and flat submerged part 1b, is arranged parallelly to the crest line of a wave, and their connecting rods 2 are coupled to energy converter parts 3 provided on dolphins 4, if the floats 1, 1 are vertically moved by the wave, the converter part 3 is actuated to absorb energy. The exposed part 1a above the water surface is formed to block-shaped in narrow width with small resistivity against horizontal wave power to extremely decrease horizontal force affected to the dolphin 4. The flat submerged part 1b is formed to sufficient length and width with large resistivity against vertical movement, and a vertical movement proper period of the whole device is determined so as to be almost coincident with a design wave period, then wave energy can be completely absorbed.

Wave-power energy recovering device

Abstract: PURPOSE:To convert wave-power into air energy efficiently by installing the constitution body having inverted L-shaped section onto the front surface of a bank body in wave incidence direction and forming the air chamber equipped with an air nozzle between the said constitution body and the bank body and constituting the inverted L-shaped top vertical part so as to be submerged below the sea level. CONSTITUTION:The constitution body 3 having inverted L-shaped section is installed, projected in the wate advance direction from the uper end of front surface of a bank body 1, and an air chamber 4 is formed between the constitution body 3 and the bank body 1. With such a constitution, wave is reflected on the front surface of the bank body 1, and duplicate wave is formed, and the water block in the air chamber 4 resonates with the wave pressure variation, and the vertical movement is converted into compression and expansion energy. At this time, air passes through a straightening valve from a nozzle 5, and the air stream is introduced into a turbine 6 and converted into rotation energy to drive a generator. Thus, electric energy can be obtained from wave-power energy.

Automatic pumping up device utilizing wave power

Abstract: PURPOSE:To utilize the wave energy efficiently, by means of a piston installed on the beach and driven by the wave power. CONSTITUTION:When a wave pushes a wave catcher board 7 energetically up to 7' position as arrow marks(a) show, the catcher board 7 compresses a spring 9 in turn. when rods 10 actuate the piston 8 along its stroke up to the position presented by the dotted line in the pressure chamber 2, water intake valve 6 is closed, while pumping-up valve 3 is opened instead, to cause the water in the pressure chamber 2 to be forced into the pressing-in tank 5. Then, when the piston is returned by the action of spring 9, the pumping up valve 3 is closed, while the water intake valve 6 is opened instead, to absorb the water form an intake port 11 into the pressure chamber 2. The water entering the pressing-in tank 5 through repetition of the above operation can be pumped up through the pumping-up tube 4, being driven by the pressure in the tank 5.

On alternative energy sources. Wave power availability in water of finite depth

Abstract: In this paper, the theory of wave height variation, due to refraction and friction on the sea bottom, is adopted to estimate the amount of mechanical power available at depths ranging from 5 to 25 m where it seems reasonable to place devices to capture and convert wave energy. The refraction theory and the power estimation method are sketched, while the evaluation of the wave power available at a location near the Italian coast of Southern Adriatic is presented as an application.