CFD investigation of pitch-type wave energy converter-rotor based on RANS simulations

Poguluri, Sunny Kumar; Ko, Haeng Sik; Bae, Yoon Hyeok

doi:10.1080/17445302.2019.1705632

Cited by 10 publications

(10 citation statements)

References 22 publications

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“…According to previous studies on the behavior of WEC rotors, the motion of a rotor has a highly nonlinear nature (Ko et al, 2019;Poguluri et al, 2019a;Poguluri et al, 2019b), which is attributed to the asymmetrical shape of a underwater rotor shape, the nonlinearity of a rotor's restoring moment, and the effects of nonlinear viscous damping moment. Motion response based on linear potential theory is very similar to the actual motion response of a rotor when the rotational displacement of a rotor is very small (Kim et al, 2019a); however, different motion responses from a linear response nature are exhibited when the rotational displacement increases owing to the increased height of the incident wave.…”

Section: Numerical Analysis Results Based On Cfdmentioning

confidence: 99%

“…When multiple rotors are arrayed, the rotor behavior pattern becomes more difficult to predict owing to the nonlinear nature and the hydrodynamic interactions with neighboring rotors. Therefore, the behavior of one rotor was simulated using a commercial CFD code to analyze the characteristics of motion in previous studies (Ko et al, 2019;Poguluri et al, 2019a;Poguluri et al, 2019b); a 3D CFD analysis was performed for three arrayed rotors in this study. shows the pattern at 57.5 s of a simulation.…”

Section: Numerical Analysis Results Based On Cfdmentioning

confidence: 99%

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Performance Analysis of Multiple Wave Energy Converters due to Rotor Spacing

Poguluri

Kim

et al. 2021

J. Ocean Eng. Technol.

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A wave energy converter (WEC) that generates electrical energy from wave energy is a subject of high research interest in academia. Salter's duck, which is a pitch-type WEC positioned on the water surface to primarily convert wave energy into rotational kinetic energy of a floating body (rotor), is one of the oldest WECs and has been researched since the 1970s (Salter et al., 1975). Salter's duck maximizes wave energy absorption by designing the front and rear shapes differently and thus is theoretically known to have nearly 90% energy absorption efficiency (Swift-Hook et al., 1975). Several recent studies in South Korea have designed Salter's duck-type WECs suitable for the western waters of Jeju Island. The design parameters and performance of a rotor have been verified through a parametric study of optimal motion performance using the wave data of the western waters of Jeju Island (Poguluri and Bae, 2018), a study on estimating viscous coefficients of a rotor using computational fluid dynamics (CFD) (Poguluri et al., 2019a), and a numerical and experimental study on the linear behavior of a rotor (Kim et al., 2019a). These previous studies, however, focused on only one WEC rotor, so the effects of hydrodynamic interactions between adjacent modules must be analyzed considering how multiple WECs are simultaneously installed in the seas in general (Kim et al., 2020). Previous studies on analyzing dynamic behavior by arranging multipleWECs include an analysis of multiple cylindrical WECs in a heaving motion in the frequency domain (Lee et al., 2018) and in the time domain (Bae and Lee, 2017) as well as a study on optimal arrangement for improving the overall performance of multiple cylindrical WECs (Kim and Bae, 2019b). In these studies, a multibody analysis was performed for cylindrical WECs in the frequency domain to which a linear potential theory was applied, based on which the motion performance of individual WECs was evaluated by solving the coupled equations of motion in the time domain. An approach for computing performance changes and interactions may be effective for multiple cylindrical WECs with a fairly weak nonlinearity of motions; however, there are limitations in examining performance changes and interactions of arrayed WEC rotors based only on linear potential theory, because asymmetrical WEC rotors applied in this study have a

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Section: Numerical Analysis Results Based On Cfdmentioning

confidence: 99%

Section: Numerical Analysis Results Based On Cfdmentioning

confidence: 99%

Performance Analysis of Multiple Wave Energy Converters due to Rotor Spacing

Poguluri

Kim

et al. 2021

J. Ocean Eng. Technol.

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“…Geometry details of principle particulars; moment of inertia in x-, y-, and z-directions; and hydrostatic properties are listed in Table 1. With the presented background, the modeling of multiple WEC rotors is considered an extension of the framework of isolated WEC rotors carried out in previous studies [27][28][29][30][31]. The interaction of multiple WEC rotors is investigated in regular waves on the basis of linear boundary element method (BEM) (using WAMIT) and nonlinear CFD (using Star-CCM+).…”

Section: Mathematical Model and Experimental Setupmentioning

confidence: 99%

“…The advantage of any numerical model can be nullified if unsuitable settings are selected. The first and second authors performed an in-depth sensitivity analysis on the single WEC rotor and compared the linear BEM and nonlinear CFD results with the findings in the literature and experimental results in Poguluri and Bae and Poguluri et al, respectively [27,28]. The details of the NWT used for validation can be found in [28].…”

Section: Validationmentioning

confidence: 99%

“…An optimal motion performance of the WEC rotor has been designed to suit the western part of the Jeju Island in South Korea by performing systematic design parameters using linear BEM [27]. Poguluri et al [28] carried out a thorough CFD-based sensitivity analysis using quasi-2D wave generation and its interaction with the WEC rotor. They concluded that the simulation parameters with wave forcing zone of one wavelength, grid aspect ratio of four, interface momentum dissipation (IMD) with artificial viscosity = 1.0 along with high resolution interface capturing method, and standard low-Re k-ε model can predict highly accurate long-term simulations of wave and WEC rotor interactions.…”

Section: Introductionmentioning

confidence: 99%

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Hydrodynamic Analysis of a Multibody Wave Energy Converter in Regular Waves

2021

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A performance assessment of wave power absorption characteristics of isolated and multiple wave energy converter (WEC) rotors was presented in this study for various wave-heading angles and wave frequencies. Numerical hydrodynamic analysis of the WEC was carried out using the three-dimensional linear boundary element method (BEM) and nonlinear computational fluid dynamics (CFD). Experimental results were used to validate the adopted numerical models. Influence with and without power take-off (PTO) was estimated on both isolated and multiple WEC rotors. Furthermore, to investigate the interaction effect among WECs, a q-factor was used. Incorporation of viscous and PTO damping into the linear BEM solution shows the maximum reduction focused around peak frequency but demonstrated an insignificant effect elsewhere. The q-factor showed both constructive and destructive interactions with the increase of the wave-heading angle and wave frequencies. Further investigation based on the prototype WEC rotor was carried, and calculated results of the linear BEM and the nonlinear CFD were compared. The pitch response and q-factor of the chosen wave frequencies demonstrated satisfactory consistency between the linear BEM and nonlinear CFD results, except for some wave frequencies. Estimated optimal time-averaged power using linear BEM show that the maximum extracted power close to the zero wave-heading angle around the resonance frequency decreases as the wave-heading angle increases. Overall, the linear BEM on the extracted power is overestimated compared with the nonlinear CFD results.

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