Hydrodynamic coefficients of a submerged pulsating sphere in finite depth

Lopes, D.B.S.; Sarmento, António

doi:10.1016/s0029-8018(01)00081-6

Cited by 6 publications

(1 citation statement)

References 5 publications

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“…The added masses A 33 and A 37 can be evaluated using various methods (e.g. Hulme 1982;Lopes & Sarmento 2002). As seen from figure 2, the added mass A 37 is negative, but A 33 + A 37 r is positive for r < 0.5.…”

Section: Heaving Pulsating Spherementioning

confidence: 99%

Wave energy absorption by a floating air bag

et al. 2016

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A floating air bag, ballasted in water, expands and contracts as it heaves under wave action. Connecting the bag to a secondary volume via a turbine transforms the bag into a device capable of generating useful energy from the waves. Small-scale measurements of the device reveal some interesting properties, which are successfully predicted numerically. Owing to its compressibility, the device can have a heave resonance period longer than that of a rigid device of the same shape and size, without any phase control. Furthermore, varying the amount of air in the bag is found to change its shape and hence its dynamic response, while varying the turbine damping or the air volume ratio changes the dynamic response without changing the shape.Comment: Revised version submitted to Journal of Fluid Mechanic

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Section: Heaving Pulsating Spherementioning

confidence: 99%

Wave energy absorption by a floating air bag

et al. 2016

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Study on Hydrodynamic Coefficients of Double Submerged Inclined Plates

Wang

Zhang

2018

China Ocean Eng

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The effects of yawing motion with different frequencies on the hydrodynamic performance of floating vertical-axis tidal current turbines

Wang

Sun

Sheng

et al. 2016

Applied Ocean Research

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Under real sea conditions, the hydrodynamic performance of floating vertical-axis tidal current turbines is affected by waves and currents. The wave circular frequency is a significant factor in determining the frequencies of the wave-induced motion responses of turbines. In this study, the ANSYS-CFX software (manufacturer: ANSYS Inc., Pittsburgh, Pennsylvania, United States) is used to analyse the hydrodynamic performance of a vertical-axis turbine for different yawing frequencies and to study how the yawing frequencies affect the main hydrodynamic coefficients of the turbine, including the power coefficient, thrust coefficient, lateral force coefficient, and yawing moment coefficient. The time-varying curves obtained from the CFX software are fitted using the least-squares method; the damping and added mass coefficients are then calculated to analyse the influence of different yawing frequencies. The simulation results demonstrate that when analysing non-yawing turbines rotating under constant inflow, the main hydrodynamic coefficient time-varying curves of yawing turbines exhibit an additional fluctuation. Furthermore, the amplitude is positively correlated with the yawing frequency, and the oscillation amplitudes also increase with increasing yawing frequency; however, the average values of the hydrodynamic coefficients (except the power coefficient) are only weakly influenced by yawing motion. The power coefficient under yawing motion is lower than that under non-yawing motion, which means that yawing motion will cause the annual energy production of a turbine to decrease. The fitting results show that the damping term and the added mass term exert effects of the same level on the loads and moments of vertical-axis turbines under yawing motion. The results of this study can facilitate the study of the motion response of floating vertical-axis tidal current turbine systems in waves.

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Hydrodynamic coefficients of a submerged pulsating sphere in finite depth

Cited by 6 publications

References 5 publications

Wave energy absorption by a floating air bag

Wave energy absorption by a floating air bag

Study on Hydrodynamic Coefficients of Double Submerged Inclined Plates

The effects of yawing motion with different frequencies on the hydrodynamic performance of floating vertical-axis tidal current turbines

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