Wave interaction with an oscillating wave surge converter, Part I: Viscous effects

Wei, Yanji; Rafiee, Ashkan; Henry, Alan S.; Dias, Frédéric

doi:10.1016/j.oceaneng.2015.05.002

Cited by 103 publications

(87 citation statements)

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“…Recent laboratory tests and numerical simulations have confirmed that vortices are generated and shed from the tips of the flap at each half wave period [10]. Hence, to incorporate the dissipative effects due to viscosity, we introduce a so-called 'dissipative surface' D close to the flap's edge, which occupies the region 1 2 w < |y | < 1 2 (w + ) as shown in figure 1(b) and figure 2.…”

Section: Mathematical Modelmentioning

confidence: 99%

“…In this paper,¯ is treated as an empirical quantity that may be determined through dedicated laboratory tests [16,23,13]. The lateral extent of the dissipative surface in (9) is chosen to reflect the characteristic size of the vortices shed from the edges of the flap as observed in laboratory tests [10].…”

Section: Mathematical Modelmentioning

confidence: 99%

“…However, recent experimental wave tank tests and computational fluid dynamics (CFD) simulations have found that flow separation effects occur at the flap's tips [10]. The numerical simulations in [10] are carried out using the commercial CFD package ANSYS Fluent, and a comparison to laboratory tests shows that such an approach can accurately capture local features of the flow, as well as overall body motion. Unfortunately, the time-consuming nature of wave tank testing and CFD simulations prevented a parametric study from being conducted.…”

Section: Introductionmentioning

confidence: 99%

“…However, neither of these conditions are satisfied in the current mathematical modelling of flap-type WECs. In the first place, the diffraction parameter of a flap-type WEC is O(1) in typical environmental conditions [10]. Secondly, the linearity assumption relies on KC 1, hence the validity of using a Morisontype drag law for flap-type WECs within the framework of linear potential flow theory is questionable.…”

Section: Introductionmentioning

confidence: 99%

“…In this way, the effects of viscous dissipation are confined to the region around the flap's tips, where they are known to occur [10]. This modelling approach is adopted in [13] to eliminate the unphysical spikes in the resonant free-surface of a moonpool that are predicted by inviscid potential flow theory.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

A new model of viscous dissipation for an oscillating wave surge converter

Cummins

Dias

2016

J Eng Math

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General rightsCopyright for the publications made accessible via the Edinburgh Research Explorer is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. Take down policyThe University of Edinburgh has made every reasonable effort to ensure that Edinburgh Research Explorer content complies with UK legislation. If you believe that the public display of this file breaches copyright please contact openaccess@ed.ac.uk providing details, and we will remove access to the work immediately and investigate your claim. A mathematical model of an oscillating wave surge converter is developed to study the effect that viscous dissipation has on the behaviour of the device. Recent theoretical and experimental testing have suggested that the standard treatment of viscous drag (e.g., Morison's equation) may not be suitable when the effects of diffraction dominate the wave torque on the device. In this paper, a new model of viscous dissipation is presented and explored within the framework of linear potential flow theory, and application of Green's theorem yields a hypersingular integral equation for the velocity potential in the fluid domain. The hydrodynamic coefficients in the device's equation of motion are then calculated, and used to examine the effect of dissipation on the device's performance. A Haskind relationship, expressing the link between the scattering-and radiation-potential problems is derived, and its connection to existing Haskind relations is explored. A sensitivity study of the device's power capture to the magnitude of the dissipation present in the system is carried out for a selection of device widths. The results of the sensitivity study are explained with reference to existing experimental and numerical data. A special focus is given to the effects of dissipation on the performance of a device whose pitching motion is tuned to resonate with the incoming waves.Response to Reviewers: In order to get the bibliography into the right format for the journal, we needed to create a new .bst file (spbasic-unsrt.bst), so please note this when compiling/proofing. Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation

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Section: Mathematical Modelmentioning

confidence: 99%