Showing papers on "Wave power published in 1989"

Modeling of a plasma column produced and sustained by a traveling electromagnetic surface wave

Abstract: We present an improved model of a plasma column produced and sustained by a traveling azimuthally symmetric electromagnetic surface wave. The axial density profile of the column as well as the wave dispersion and field and power characteristics are now specified by five parameters: (i) the collision frequency for momentum transfer ν, ν<ω (ω being the wave angular frequency), (ii) the number σ=ωR/c (R is the plasma column radius, c the speed of light), (iii) the number β indicating the gas‐discharge regime (B=0 for the diffusion regime and 0<β≤2 for the bulk recombination one), (iv) the permittivity of the container (glass tube) ed, and (v) the number γ=1+d/R (d denoting the thickness of the tube), the last two parameters having been neglected earlier. The influence of ed and γ on the wave dispersion properties and the axial profiles of the plasma density, wave power, and wave electric field components has been studied numerically. Our improved model is tested with the experimental data [A. Sola, A. Gamero...

Nonlinear evolution of the auroral electron beam

Abstract: The nonlinear spatial evolution, from the source to the atmosphere, of the auroral electron beam and the beam-generated electrostatic whistler noise was studied, calculating changes in beam parameters from equations for the conservation of total particle and wave energy and momentum flux density. Wave power fluxes were calculated by numerically integrating the wave kinetic equations, and the levels of beam-generated noise were determined by using thermal levels of Cerenkov radiation as a source. It was found that beam parameters evolve on ionospheric scale lengths, and their positive slope feature in velocity space is maintained over altitudes measured in thousands of kilometers of altitude, even though they can generate wave energy density fluxes sufficient to modify the ionospheric density profile.

Distribution of Deep Water Wave Power Around the Indian Coast Based on Ship Observations

Abstract: The ship reported swell data published in the Indian Daily Weather Reports for the period from 1968 to 1983 are compiled for the seas around India which are divided into 10 grids each of 5° latitude and 5 ° long itude. The percentage distribution of wave power in different directions over a year for each grid is presented. The annual mean wave power along the Indian coast varies from 11.4 to 15.2 KW per metre length of wave crest with a maximum of 15.2 KW for the regions off south Kerala and south Tamilnadu coasts and a minimum of 11.4 KW off the Andhra coast. Computation based on the measured waves of one year duration show that the annual mean wave power available in the grids 3 and 9 is lower and is only about 53 and 77 percent respectively of the annual mean wave power computed based on ship reported wave data. About 55 to 65 percent of the annual total wave power is contributed during the southwest monsoon period from June to September. Wave power available in February, March and April in general is the lowest. Wave activity is found to be high both during the southwest and the northeast monsoons along the east coast bordering the Bay of Bengal whereas it is confined predominantly to the southwest monsoon period in the case of the west coast bordering the Arabian Sea.

Floating wave-removing type wave-power generating device

Abstract: PURPOSE:To efficiently absorb wave energy while obtain a wave removing function by continuously providing air chambers for absorbing wave energy while providing a bottom board, an outside bulkhead board, and a vibration suppressing fin on each air chamber. CONSTITUTION:A longitudinal box type body which has buoyancy chambers in front and in rear and the lower portion of which is opened, is partitioned by means of partition walls each of which forms a part of each outside bulkhead board 6 into a number of air chambers 2. The back side wall of the longitudinal box type body is extended downward forming an extended portion 2a and a bottom board 5 is installed on the lower end thereof. Further, the bottom board 5 is extended to the rear of the extended portion 2a to form a vibration suppressing fin 7. A device thus formed is floatingly installed in sea water, an an air-turbine generator is mounted on a nozzle 4 provided on the top portion of each air chamber 2. Thereby, wave energy can be efficiently absorbed by utilizing the vibrating water column movement in the air chambers 2 while obtaining a wave removing function.

Wave power generator

Abstract: A generator device suitable to convert wave energy from the sea to use in, say, the production of electricity comprises a support 6, which may be moved up and down on the shore to accommodate changes in tide level, and float means 14, (44) which can reciprocate in response to the movement of the waves 4. The float means is linked through a suitable linkage 20, (46) to a piston and cylinder arrangement 16, 18 (48) adapted to provide fluid pressure to an energy store device or to a generator. The piston rods of the arrangements 16, 18 may be operated by a cam 24 which moves in response to the float movement, and the fluid pumped may comprise air or hydraulic fluid. The support may be inclined (Fig 3).

Wave power device

Abstract: The wave power device consists of a vented chamber or chambers wherein rising water in the chamber or chambers produced by waves is allowed free or controlled ingress by means of pivoted flaps or other forms of control and wherein falling water from the chamber or chambers is controlled to provide power. The device may be located within a ship or vessel to provide propulsion and/or retardation thereof (Figure 1), or it may be attached to the sea bed for the generation of electricity by means of one or more water turbines (Figure 2).

Compressed air storage type power generating method by wave power

Abstract: PURPOSE:To secure inexpensive power by installing a weight and a balancing weight in a floating body, building up the extent of floating energy by waves, and producing compressed air. CONSTITUTION:Motion of a floating body 1 is connected to a vertical frame 12 attached to an interval between a support beam 13 and a guide beam 14 by a chain coupler 5 via a block 15, while this vertical frame 12 is connected to a piston rod 10 by a universal joint 6, working on an air compressor 16 in a pump room 11, and compressed air is produced. The produced compressed air is stored in a pipe type tank 18 via an outlet pipe 17. The compressed air stored is possible to generate stable power owing to averaged air pressure irrespective of a state of waves and the ebb and flow of the tide because the pipe type tank 18 is extended up to a spot suitable for power generation and generates power in this way.

Study on Pneumatic Wave Power Conversion System with Water Valve Rectifier

Abstract: We experimentally and theoretically studied the energy conversion characteristics on a new type of wave power conversion system with water valves. The hydraulic model experiment was performed in regular waves using a nozzle as a dummy load with some parameters of submerged depth of the water valve, nozzle ratio, height of incident wave and wave period. It was proved from the experimental results that the efficiency of the water valve is equal to or higher than that of such a mechanical valve as conventional flap valves, that the influences of wave period and load change to the new system is less than to the conventional oscillating water column type wave power converter. In addition, it was confirmed that the water valve was effective as a safety system.

Wave Power Resource Investigations in New Zealand

Abstract: The New Zealand wave power is greatest south of the South Island where estimates predict the average power will exceed 100 kW/m. Electricorp Production has funded the deployment of a wave rider buoy off the south of the South Island to measure the wave resource in detail. This buoy was deployed in February 1989 for about one year in a depth of about 100m and about 30 km off the coast. Land based microseismic recordings are processed and related to the wave energy (in particular the swell).

Line fault detector

Abstract: PURPOSE:To detect a fault of a radio line due to the presence in an interference wave in real time with simple constitution by detecting the power of an out-band interference and obtaining a ratio of it to a main wave power CONSTITUTION:The 1st detection circuit 15 is provided with a filter 15a extracting only the center band of a main wave and a detector 15b to detect the power at the center band of the main wave The 2nd detection circuit 16 detects the power of the entire band of the main wave A detection circuit 17 obtains an out-band interference power versus main wave power based on the output of the 1st detection circuit 15 and the output of the 2nd detection circuit 16 and gives the result to a terminal 18 In the absence of the interference wave, although the main wave power versus out-band interference power is constant, the ratio is varied by the power of the interference wave when any interference wave exists Thus, the line fault due to the presence of the interference is detected