Numerical Solution of Body-Exact Problem in the Time Domain

This paper presents the design concept of a hinged-type wave energy converter, Sea Wave Energy Extraction Device (Sea-WEED), and associated numerical and experimental studies of its performance in regular waves. The device is considered as an improved attenuator. A SeaWEED unit consists of four modules that are connected by rigid truss structures. The fourmodule array includes a non-energy producing nose module in the front, followed by two energy producing modules, and another non-energy producing module at the rear. A potential-flow-based time-domain program with the Lagrange multiplier approach was developed to simulate the dynamics of multiple constrained bodies. Model tests of a 1:35 scale model with and without the power takeoff (PTO) units were carried out to validate the numerical method. Friction dampers were designed and manufactured to mimic the PTO units. The validated time-domain method was applied to predict the absorbed power by the device in regular waves.

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“…According to the work of Danmeier [26] and Qiu and Peng [27], equations of motion for the SeaWEED system can be obtained as follows.…”

Section: Numerical Modelingmentioning

confidence: 99%

Experimental studies and time-domain simulation of a hinged-type wave energy converter in regular waves

Peng

Qiu

Meng

et al. 2020

Mar Syst Ocean Technol

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“…More recently, Bai and Eatock Taylor (2009) applied the domain decomposition method to investigate fully nonlinear wave interaction of fixed and freely floating flared structures. Qiu and Peng (2013) used a panel-free method for the body-exact problem in the time domain. One of the important numerical problems of an MEL-type time-domain solution scheme for the full nonlinear floating body problem is associated with the coupling between hydrodynamic forces and rigid body motions which tend to cause numerical instability inhibiting long-duration time-domain simulation.…”

Section: Introductionmentioning

confidence: 99%

Time-domain simulation of large-amplitude wave–structure interactions by a 3D numerical tank approach

Ganesan

Sen

2015

J. Ocean Eng. Mar. Energy

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A time-domain 3D Rankine panel method based on a simplified variant of the mixed Eulerian-Lagrangian scheme under certain approximations is developed for studying steep nonlinear waves interacting with practical ship and offshore configurations at zero speed. Appropriate techniques have been developed that enable the method to produce very long-duration simulation results. Two levels of time-domain computations are performed: (1) a fully linear formulation where all external forces are computed on the mean wetted surface, and (2) an approximate nonlinear computation where the hydrodynamics interaction forces (diffraction and radiation forces) are determined on the mean surface and the forces arising from the incident steep waves and hydrostatic restoring forces are determined based upon the exact wetted surface under the nonlinear incident wave. Numerical computations for three practical marine structures, the barge, the S175 hull, and the semisubmersible are presented. The linear computations for which very longduration simulations are achievable from the present method are validated against results from other available methods. As the method is developed for stationary floating bodies undergoing oscillation about their mean location, it cannot be applied for a fully unrestrained body which can freely drift. In absence of physical restraints, the approximate nonlinear calculation requires imposition of artificial constraints partially or fully restraining the horizontal motions. Very long-duration simulations under the influence of steep nonlinear large-amplitude waves for all the three structures considered could be achieved. Comparative studies between different force and motion components in large-amplitude waves from linear and the approximate nonlinear computations are made to bring out the influence of the incident wave nonlinearities on these structures. It is found that the nonlinearities of the forces and motions are strongly dependent on the above water hull geometry. Compared to a small water-plane area hull (the semisubmersible), or a wall-sided hull (the barge), a flared hull (S175) results in pronounced nonlinear features in the forces and motion time-histories.

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Vertical integral method incoporated with multi-domain HOBEM for time domain calculation of hydrodynamics of forward speed SHIP

Zhou

Zhu

Chen

et al. 2020

Applied Ocean Research

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Numerical Solution of Body-Exact Problem in the Time Domain

Cited by 6 publications

References 8 publications

Experimental studies and time-domain simulation of a hinged-type wave energy converter in regular waves

Experimental studies and time-domain simulation of a hinged-type wave energy converter in regular waves

Time-domain simulation of large-amplitude wave–structure interactions by a 3D numerical tank approach

Vertical integral method incoporated with multi-domain HOBEM for time domain calculation of hydrodynamics of forward speed SHIP

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