## Abstract

A method for calculating the energy take-out from a single wave energy converter is presented. The converter consists of a buoy connected via a hose pump to a submerged plate. The equations of motion of the buoy and plate are solved linearly in the frequency domain, which shows that frequency dependent hydrodynamic properties can be used. The hose pump is treated as a complex spring, the real part corresponding to a spring and the imaginary part corresponding to a time independent damping factor. The damping factor multiplied by the amplitude of the hose pump is a measure of the work done by the pump. The drag force is linearized by setting the energy dissipation for a period equal in both the non-linear and the linear cases. The emphasis in this report is placed on the calculation of the frequency dependent hydrodynamic properties, such as the wave excited forces and the hydrodynamic coefficients. The structure is considered to be large in comparison with the wave length and, therefore, the diffraction theory has been used. A method of calculating the forces that act on the bodies is presented, as well as the interaction between the bodies. This two-body problem is solved analytically.
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## Citation Formats

Berggren, L.
Energy take-out from a wave energy device. A theoretical study of the hydrodynamics of a two-body problem consisting of a buoy and a submerged plate.
Sweden: N. p.,
1992.
Web.

Berggren, L.
Energy take-out from a wave energy device. A theoretical study of the hydrodynamics of a two-body problem consisting of a buoy and a submerged plate.
Sweden.

Berggren, L.
1992.
"Energy take-out from a wave energy device. A theoretical study of the hydrodynamics of a two-body problem consisting of a buoy and a submerged plate."
Sweden.

@misc{etde_10113651,

title = {Energy take-out from a wave energy device. A theoretical study of the hydrodynamics of a two-body problem consisting of a buoy and a submerged plate}

author = {Berggren, L}

abstractNote = {A method for calculating the energy take-out from a single wave energy converter is presented. The converter consists of a buoy connected via a hose pump to a submerged plate. The equations of motion of the buoy and plate are solved linearly in the frequency domain, which shows that frequency dependent hydrodynamic properties can be used. The hose pump is treated as a complex spring, the real part corresponding to a spring and the imaginary part corresponding to a time independent damping factor. The damping factor multiplied by the amplitude of the hose pump is a measure of the work done by the pump. The drag force is linearized by setting the energy dissipation for a period equal in both the non-linear and the linear cases. The emphasis in this report is placed on the calculation of the frequency dependent hydrodynamic properties, such as the wave excited forces and the hydrodynamic coefficients. The structure is considered to be large in comparison with the wave length and, therefore, the diffraction theory has been used. A method of calculating the forces that act on the bodies is presented, as well as the interaction between the bodies. This two-body problem is solved analytically. The present solution is compared with a numerical one and an analytical one, the latter, however, treats simply a single buoy riding in the waves. The calculated energy take-out of the present model is compared with a time domain dependent model, and reasonable agreement has been found. (7 refs., 18 figs., 2 appendices titled: `Hydrodynamic coefficients of a wave energy device consisting of a buoy and a submerged plate`, and `Forces on a wave-energy module`.).}

place = {Sweden}

year = {1992}

month = {Dec}

}

title = {Energy take-out from a wave energy device. A theoretical study of the hydrodynamics of a two-body problem consisting of a buoy and a submerged plate}

author = {Berggren, L}

abstractNote = {A method for calculating the energy take-out from a single wave energy converter is presented. The converter consists of a buoy connected via a hose pump to a submerged plate. The equations of motion of the buoy and plate are solved linearly in the frequency domain, which shows that frequency dependent hydrodynamic properties can be used. The hose pump is treated as a complex spring, the real part corresponding to a spring and the imaginary part corresponding to a time independent damping factor. The damping factor multiplied by the amplitude of the hose pump is a measure of the work done by the pump. The drag force is linearized by setting the energy dissipation for a period equal in both the non-linear and the linear cases. The emphasis in this report is placed on the calculation of the frequency dependent hydrodynamic properties, such as the wave excited forces and the hydrodynamic coefficients. The structure is considered to be large in comparison with the wave length and, therefore, the diffraction theory has been used. A method of calculating the forces that act on the bodies is presented, as well as the interaction between the bodies. This two-body problem is solved analytically. The present solution is compared with a numerical one and an analytical one, the latter, however, treats simply a single buoy riding in the waves. The calculated energy take-out of the present model is compared with a time domain dependent model, and reasonable agreement has been found. (7 refs., 18 figs., 2 appendices titled: `Hydrodynamic coefficients of a wave energy device consisting of a buoy and a submerged plate`, and `Forces on a wave-energy module`.).}

place = {Sweden}

year = {1992}

month = {Dec}

}