Wave power

About: Wave power is a research topic. Over the lifetime, 2671 publications have been published within this topic receiving 41439 citations. The topic is also known as: wind wave energy & sea wave energy.

ULF wave power features in the topside ionosphere revealed by Swarm observations

Abstract: Recently developed automated methods for deriving the characteristics of ultra low frequency (ULF) waves are applied to the Swarm data sets in order to retrieve new information about the near-Earth electromagnetic environment. Here we present the first ULF wave observations by Swarm, analyzing 1 year data from the mission. We find evidence for the decay of the amplitude of the Pc3 (20–100 mHz) signal with altitude in the topside ionosphere as predicted by theoretical models of wave propagation. We show that the major characteristics of the Swarm ULF power maps generally agree with respect to the wave activity seen by the upper satellite and the lower pair of satellites when the power spectrum of the upper satellite is shifted by 1 h in magnetic local time. Moreover, a puzzling enhancement, not predicted by current ULF wave theories, of compressional Pc3 wave energy was revealed by Swarm in the region of South Atlantic Anomaly.

Performance of Wave Power Generating System Installed In Breakwater At Sakata Port In Japan

Abstract: The wave power generating system using the Wells turbine is installed in the breakwater in Sakata port, Japan, and consists of the air chamber, turbine, generator and safety devices. The purposes of this paper are to reveal the characteristics of each component in this system with the experimental data in the real sea, and to evaluate the accuracy of numerical models used in the simulation. The performance of Wells turbine is examined in detail for the unsteady and full-scale condition, comparing the data of the 1/4 scale model with the steady full-scale one. As for the motion of water in the air chamber, the eigenfunction expansion method is introduced, and the wave height measured 275m away from the chamber is employed for the input of the simulation. It is found that the performance of the system for the wave can be evaluated accurately with the steady-characteristics of the turbine, in the condition that the stall does not happen on the rotor. The angle of attack for the stall depends on the wave characteristics such as the magnitude of unsteadiness, requiring many trials to get the stall angle used by the calculations. The error of the simulation for the total system is finally predicted to be less than 20% when the wave comes within the region of about 20 degree deviation angle.

Analysis of linear wave power generator model with real sea experimental results

Abstract: This study presents the dynamic modelling of a linear permanent magnet generator for extracting energy from ocean waves. Translator position, calculated from measured generator voltage, is used as input for the simulation model. Instantaneous power from the simulation model has been compared with the measurements from the Lysekil research site. The power output from the model considering the air gap flux variation is precisely matching with the measured values before core saturation. The generator dynamic model is modified by including the saturation effect. Although a simple mathematical expression is considered for representing the saturation, the model gives accurate power spectrum close to the experimental results. The presented model is a first step towards the system model that can simulate the entire electric system including electric grid. As such, the generator model can be used for further analysis of the wave energy conversion system.

Apparatus for converting wave energy into electrical energy

Abstract: An apparatus for converting wave energy into electrical energy includes a wave power generation unit including a frame and float guides. A wave power generation float is joined to the float guides for vertical motion in response to the wave energy. The wave power generation float includes at least one wave power conversion module. The wave power conversion module includes a module case and an air sealing tube formed in the module case for generally preventing fluids from entering the module case. A power transmission cable transmits electrical energy where one end of the power transmission cable passes through the air sealing tube and is joined to the frame. A cable reel winds and unwinds the power transmission cable. A power transmission drive translates a bidirectional rotation of an input shaft into a unidirectional rotation. A generator generates electrical energy in response to the unidirectional rotation.

Mechanism for formation of lutoclines by waves

Abstract: The mechanism by which a suspended fine-sediment-induced pycnocline, or lutocline, is generated under wave action is examined. The steady-state form of the turbulent kinetic energy balance is used along with commonly invoked phenomenological arguments to obtain a formula for the height of the lutocline as a function of wave and suspended sediment properties. This formula is then used in conjunction with data on equilibrium heights of lutoclines of a suspended clay mixture in a wave flume to show that the formula holds promise as a first-order predictor of lutocline height. This height is also shown to correlate empirically with wave energy.