Showing papers on "Wave power published in 1985"

Wave-power absorption by an oscillating water column in a channel

Abstract: Wave-power absorption by an oscillating water column in a channel is studied within linear theory, and for different boundary conditions regarding the regions between the absorber and the channel walls. Particular attention is given to the effect of placing projecting sidewalls in front of the column.

Wave power converter

Abstract: An apparatus for converting power from the wave motion of a body of water comprises a chamber with an opening for receiving waves. The chamber amplifies the amplitude of the waves. The wall of the chamber preferably has protuberance adjacent the opening for smoothing the flow of water through the opening. A float within the chamber is connected to a pump for converting the energy of the waves into useful energy.

Analytical method for estimating palaeowave climate and water depth from wave ripple marks

Abstract: Analytical expressions are developed for evaluating palaeodepth and palaeowave conditions from wave ripple marks. Palaeodepth and palaeowave climate estimates can be extremely powerful predictors in reconstructions of vertical movements related to basin subsidence, local and regional ancient wave climate trends and the basin shape. The analytical expressions developed herein are applied to wave ripple marks preserved in the Lower Marine Molasse of Switzerland, western Austria and southern Germany. The results suggest that, in contrast to traditional concepts of an eustatic sea-level change, the Lower Marine Molasse regression was a result of mainly depositional processes. The subsidence rate greatly exceeded the rate of sea-level fall over a wide geographical area. Furthermore, the widening of the Lower Marine Molasse basin to the ENE is well documented by the increase of the ancient wave period and wave power, calculated from wave ripple marks found in storm deposits.

Significant Wave Height for Shallow Water Design

Abstract: Wave height parameters used in coastal and ocean engineering are grouped into three classes according to their definition bases: height statistics, energy, and monochromatic. Parameters within each class are easily interrelated for most engineering purposes. However, parameters from different classes are difficult to interrelate, particularly for shallow water applications where waves are near breaking. The often-used parameter “significant wave height” has traditionally been based on height statistics but many modern estimates are based on wave energy. A simple empirical method is developed to relate statistical and energy based significant height estimates. The method is developed with CERC laboratory flume data from a 1:30 plane slope, two samples of field data, and stream function wave theory. Since the two significant height estimates differ by over 40% in some laboratory cases, engineers should clearly recognize the distinction between them.

The Q.U.B. Axisymmetric and Multi-Resonant Wave Energy Convertors

Abstract: This paper describes the optimization of the power conversion chain and the engineering design considerations of an oscillating water column wave power device which would form part of a 2-GW power station. Novel features of the principal device described include the multi-resonant concept, which considerably widens the frequency bandwidth response, and the use of the simple highly efficient Wells self-rectifying air turbine in the secondary power conversion stage. It is concluded that using established technology wave power stations comprising sea bed mounted reinforced concrete structures could produce power for as little as 1.3p per kW-hr after the initial capital repayment period and thus the economics are similar to that of hydro-electric power.

Fundamental Research on Oscillating Water Column Wave Power Absorbers

Abstract: An oscillating water column (OWC) wave power absorber is one of the most promising devices, as well as the Salter Duck and the Clam. This paper presents a simple prediction method, in which the equivalent floating body approximation is used, for absorbing wave power characteristics of an oscillating water column device. The effects of the compressibility of air and inertia of an air turbine and electric generator on absorbed wave power are obtained by using the equivalent electric circuit concept. Both the experimental and theoretical studies are carried out in this paper.

Method of and apparatus for inspecting and/or positioning objects with wave energy using wave guides

Abstract: A system for achieving inspecting and/or positioning of an object (132) that includes: an array (133) that is operable to generate acoustic or low-frequency electromagnetic wave energy of a single or narrow band of frequencies, to transmit the wave energy to an interaction region where it interacts with the object and to transmit the wave energy, after interaction, to sensing means, sensors of the array (134) being disposed to receive the wave energy and being operable to convert the wave energy to electric signals representative of the received wave energy; a processor (137, 139, 140, 141) connected to receive the electric signal and adapted to process the signals into amplitude and/or phase information for each sensor; and an analyzer (144) to interpret the amplitude and/or phase information to derive therefrom a characteristic of the object, e.g., a geometric characteristic or an electromagnetic characteristic.

A Device for Wave Power Extraction in Coastal Structures: Field Test of a Pendular System

Abstract: Study is performed on a vertical plate type energy converter, named “Pendular System”. The device is one of the fixed type wave absorber and consists of an oscillating pendulor around the horizonta...

A Radial Wave Power Combiner Designed by Broadband Techniques

Abstract: A novel approach to achieve optimum performance from a radial wave power combiner has been developed. The design is based upon traditional matching filter synthesis techniques employed to realize octave bandwidth performance in the form of a radial wave matching filter. A radial wave power combiner which covers 720 to 1770 MHzbetween 0.1 dB points with less than 0.3 dB insertion loss has been developed in a very simple structure suitable for low cost manufacturing. This paper will discuss the evolution of the design from lumped element prototype through the final distributed network design, optimized for size, performance, and cost. The prototype hardware has found immediate application in a 1.3 kW solid state amplifier designed for linear amplification of a multitone cellular radio spectrum.

A simplified method of obtaining the response of structures from large data banks of wave power spectral densities

Abstract: A statistical method using empirical orthonormal functions (EOF's) is presented for efficiently representing large data banks of archived nondirectional wave power spectral densities (PSD's). This reduced data set is used to obtain a displacement output probability density function of an offshore structure in response to a wave field. An example is presented thai utilizes five months of NOAA estimated wave spectra taken at 4-h intervals in the Eastern Pacific Ocean. Structural Applications Software was developed to provide the output probability density function for any frequency band of interest without requiring the many tapes of original data. For nonlinear problems, a method of generating typical random wave data is discussed that will allow for Monte Carlo simulation.