Ship propulsion in waves by actively controlled flapping foils

Belibassakis, Kostas; Filippas, E.S.

doi:10.1016/j.apor.2015.04.009

Cited by 59 publications

(23 citation statements)

References 14 publications

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“…where w h i (t) denote the time-dependent nodal unknowns and H i (x) are the Hermite shape functions. A second order system of ODEs is derived when the approximate solution in Equation (25) is substituted into a discretized Equation (7) and the resulting formula is tested with the shape functions. Finally, the discretized system is written in matrix form as,…”

Section: Discretization Scheme For Femmentioning

confidence: 99%

“…The thunniform swimming mode for example, where the caudal fin of the fish performs a combination of pitching and heaving motions, identifies as the most efficient and therefore suitable for nature-inspired propulsion systems operating at high cruising speeds, see, e.g., [3,4]. Devices based on flapping foils have also been studied as auxiliary thrusters augmenting the overall ship propulsion in waves, see, e.g., the works [5][6][7][8][9] and project BIO-PROPSHIP [10]. Moreover, oscillating foils are studied for the development of hydrokinetic energy devices, see, e.g., [11][12][13] or hybrid devices with enhanced performance exploiting combined wave and tidal energy resources, see [14].…”

Section: Introductionmentioning

confidence: 99%

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A Non-Linear BEM–FEM Coupled Scheme for the Performance of Flexible Flapping-Foil Thrusters

Anevlavi

Filippas

Karperaki

et al. 2020

JMSE

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Recent studies indicate that nature-inspired thrusters based on flexible oscillating foils show enhanced propulsive performance. However, understanding the underlying physics of the fluid–structure interaction (FSI) is essential to improve the efficiency of existing devices and pave the way for novel energy-efficient marine thrusters. In the present work, we investigate the effect of chord-wise flexibility on the propulsive performance of flapping-foil thrusters. For this purpose, a numerical method has been developed to simulate the time-dependent structural response of the flexible foil that undergoes prescribed large general motions. The fluid flow model is based on potential theory, whereas the elastic response of the foil is approximated by means of the classical Kirchhoff–Love theory for thin plates under cylindrical bending. The fully coupled FSI problem is treated numerically with a non-linear BEM–FEM scheme. The validity of the proposed scheme is established through comparisons against existing works. The performance of the flapping-foil thrusters over a range of design parameters, including flexural rigidity, Strouhal number, heaving and pitching amplitudes is also studied. The results show a propulsive efficiency enhancement of up to 6% for such systems with moderate loss in thrust, compared to rigid foils. Finally, the present model after enhancement could serve as a useful tool in the design, assessment and control of flexible biomimetic flapping-foil thrusters.

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Section: Discretization Scheme For Femmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Non-Linear BEM–FEM Coupled Scheme for the Performance of Flexible Flapping-Foil Thrusters

Anevlavi

Filippas

Karperaki

et al. 2020

JMSE

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“…On numerical simulation, Belibassakis et al [8][9] carried out the hydrodynamic analysis of flapping fin and analyzed its random fluctuation at a constant forward speed, The results show that within a certain range of motion parameters, the stability of the ship has been significantly improved. At the same time, it can generate an anti-rolling moment to absorb the vibration.…”

Section: (D)-(e)) In 2008 Kenichimentioning

confidence: 99%

Propulsion Performance Analysis of Wave-powered Boats

Chang

Deng

Zhang

et al. 2020

Int. j. eng. technol. innov.

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With the development of oceanographic research and marine environment protection, mobile marine platforms are applied for ocean observation for a long journey. Wave-powered boats are capable of applying wave motion to propel itself and make a long-duration survey. This paper presents the dynamics of the wave-powered boat under the excitation of the heave motion and pitch motion. Taking the wave-powered boat with double fins as an example, the heave and pitch motions of the boat are obtained by ANSYS-AQWA firstly. Then the relationship between propulsion performance and three factors, including wave height, wave period, and restoring stiffness of torsion spring, was analyzed through multibody dynamics software ADAMS. With the increase of sea state from level 1 to level 4 the average propulsion speed increased from 0.4m/s to 1.4m/s. Under the same wave height and period, with the increase of restoring stiffness of torsion spring from 0.0125N·m/deg to 0.3N·m /deg, the propulsion speed of the wave-powered boat increases first and then decreases, and there exists an optimum stiffness. Through the calculation it is found that when the restoring stiffness of torsional spring is increased from 0.025N·m /deg to 0.2N·m /deg with the sea state level 1 to 4, the wave powered boat has better propulsion performance.

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“…As a result, these devices have gained popularity as secondary propulsion systems. References [5][6][7][8][9][10][11][12][13] provide detailed analysis of the characteristics of such systems. Also, some of the present authors were involved in the research project BIO-PROPSHIP [14] for the investigation of flapping foils.…”

Section: Introductionmentioning

confidence: 99%

A Study of Multi-Component Oscillating-Foil Hydrokinetic Turbines with a GPU-Accelerated Boundary Element Method

Koutsogiannakis

Filippas

Belibassakis

2019

JMSE

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A biomimetic semi-activated oscillating-foil device with multiple foils in a parallel configuration is studied for the extraction of marine renewable energy. For the present investigation, an unsteady boundary element method (BEM) is used for the simulation of 3D lifting flows. For this work, the device is assumed to be submerged far from the free surface and the sea bottom. However, the geometry of the body and the initial shape of the wake are general. For the numerical simulations, a high performance in-house GPU-accelerated code (GPU-BEM) is developed. For the calculation of singular integrals, an adaptive algorithm based on the Gauss-Lobatto quadrature is used. Concerning the numerical scheme of GPU-BEM, the convergence of the method was tested, the numerical characteristics were determined and the method was validated. A parametric study of a single-foil device is presented to determine the performance characteristics of such devices. Next, twin-foil devices are investigated in parallel and staggered configurations with a phase difference between the two foils. Finally, the multiple-foil parallel configuration is compared against turbines. After enhancement and further verification, the present method is proposed for the design and control of such biomimetic devices for the extraction of energy from waves and tidal currents nearshore.Foils can also be used as devices that convert tidal stream energy to other forms, i.e., electricity. In tidal energy harvesting mode, oscillating foils operate by absorbing energy from the incident current. One of the first reports on such designs is that of reference [15], and some early experiments were conducted in 1982 [16].Oscillating foils combine a pitch motion and a heave motion. In reference [17], oscillating-foil devices are classified into three categories depending on the activation mechanism of the oscillating foil. First, there are fully activated foils, where both the pitch and heave motions are prescribed. Second, there are semi-activated foils, where the pitch motion is given as input and the heave is the response to the hydrodynamic forces. Third, there are fully passive foils, where both motions are driven by the forces acting on the foil. In the present work, we study the semi-activated oscillating foil, because this alternative is a more feasible design than the fully activated system and it provides a mechanism to actively control the operation of the foils, in contrast to the fully passive design. Also, energy extraction of both waves and current is studied by the authors in [18].Moreover, efforts have been made to map the performance of oscillating foils in the energy extraction regime, i.e., parametric studies [19][20][21]. The basic parameters of the harmonic pitching motion have been mainly investigated, through experiments or numerical simulations. In [19], the authors report a power-extraction efficiency of 36.4% for a pitching amplitude of 76.3 degrees, using the FLUENT commercial software.Various studies have shown that oscillating foils can have...

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Ship propulsion in waves by actively controlled flapping foils

Cited by 59 publications

References 14 publications

A Non-Linear BEM–FEM Coupled Scheme for the Performance of Flexible Flapping-Foil Thrusters

A Non-Linear BEM–FEM Coupled Scheme for the Performance of Flexible Flapping-Foil Thrusters

Propulsion Performance Analysis of Wave-powered Boats

A Study of Multi-Component Oscillating-Foil Hydrokinetic Turbines with a GPU-Accelerated Boundary Element Method

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