Flapping wing propulsor design: An approach based on systematic 3D-BEM simulations

Politis, Gerasimos; Tsarsitalidis, Vasileios

doi:10.1016/j.oceaneng.2014.04.002

Cited by 21 publications

(10 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Factors that may produce effects on the hydrodynamic performance have been studied since early periods. It has been proven that a combined oscillating foil performs better than a pure heaving or a pure pitching foil in most conditions [4,5]. Moreover, the phase difference and pivot points do have a perfect value, which we applied here, for more efficient propulsion described in the work of Lin and Wu [6].…”

Section: Introductionmentioning

confidence: 90%

Investigation on Hydrodynamic Performance of Flapping Foil Interacting with Oncoming Von Kármán Wake of a D-Section Cylinder

Wang

et al. 2021

JMSE

View full text Add to dashboard Cite

Flapping foils are studied to achieve an efficient propeller. The performance of the flapping foil is influenced by many factors such as oncoming vortices, heaving amplitude, and geometrical parameters. In this paper, investigations are performed on flapping foils to assess its performance in the wake of a D-section cylinder located half a diameter in front of the foil. The effects of heaving amplitude and foil thickness are examined. The results indicate that oncoming vortices facilitate the flapping motion. Although the thrust increases with the increasing heaving amplitude, the propelling efficiency decreases with it. Moreover, increasing thickness results in higher efficiency. The highest propelling efficiency is achieved when the heaving amplitude equals ten percent of the chord length with a symmetric foil type of NACA0050 foil. When the heaving amplitude is small, the influence of the thickness tends to be more remarkable. The propelling efficiency exceeds 100% and the heaving amplitude is 10% of the chord length when the commonly used equation is adopted. This result demonstrates that the flapping motion extracts some energy from the oncoming vortices. Based on the numerical results, a new parameter, the energy transforming ratio (RET), is applied to explicate the energy transforming procedure. The RET represents that the flapping foil is driven by the engine or both the engines and the oncoming vortices with the range of RET being (0, Infini) and (−1, 0), respectively. With what has been discussed in this paper, the oncoming wake of the D-section cylinder benefits the flapping motion which indicates that the macro underwater vehicle performs better following a bluff body.

show abstract

Section: Introductionmentioning

confidence: 90%

Investigation on Hydrodynamic Performance of Flapping Foil Interacting with Oncoming Von Kármán Wake of a D-Section Cylinder

Wang

et al. 2021

JMSE

View full text Add to dashboard Cite

show abstract

“…Selection of the swimming mode to serve as inspiration for the artificial devices closely depends on hydromechanical aspects of the application itself. 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].…”

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

View full text Add to dashboard Cite

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.

show abstract

“…Apart from this mode of operation, foils performing flapping motion are also studied as efficient propulsion systems. Research and development of flapping wings is supported by extensive experimental, theoretical and numerical studies, with results that show that in optimal conditions, such systems can achieve high thrust levels (see, e.g., [2][3][4]). Flapping wings can also be used as "thrust augmentation devices" fitted on the hulls of ships.…”

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

View full text Add to dashboard Cite

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...

show abstract

Flapping wing propulsor design: An approach based on systematic 3D-BEM simulations

Cited by 21 publications

References 15 publications

Investigation on Hydrodynamic Performance of Flapping Foil Interacting with Oncoming Von Kármán Wake of a D-Section Cylinder

Investigation on Hydrodynamic Performance of Flapping Foil Interacting with Oncoming Von Kármán Wake of a D-Section Cylinder

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

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

Contact Info

Product

Resources

About