Third-harmonic wave diffraction by a vertical cylinder

Malenica, Šime; Molin, Bernard

doi:10.1017/s0022112095004071

Cited by 153 publications

(114 citation statements)

References 6 publications

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“…There is no far-field wave generation predicted by the model. Malenica & Molin (1995) developed a complete third-order diffraction model, including far field wave generation, in finite water depth.…”

Section: Introductionmentioning

confidence: 99%

Higher harmonic wave loads on a vertical cylinder in finite water depth

Kristiansen

Faltinsen

2017

J. Fluid Mech.

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The theory by Faltinsen et al. (1995) (FNV) for calculation of higher-order wave loads in deep water, on a vertical, free-surface piercing, circular, bottom-mounted, non-moving cylinder, based on potential flow of an incompressible fluid, is generalized to finite water depth. Systematic regular wave experiments are carried out, and the harmonics of the horizontal wave loads are compared with the generalized FNV theory. Horizontal force and mudline overturning moment are studied. The main focus is on the third harmonic of the loads, although all harmonics one to five are considered. The theoretically predicted third harmonic loads are shown to agree well with the experiments for small-to-medium wave steepnesses, up to a rather distinct limiting wave steepness. Above this limit, the theory over-predicts, and the discrepancy in general increases monotonically with increasing wave steepness. The local Keulegan-Carpenter (KC) number along the axis of the cylinder indicate that flow separation will occur for the wave conditions where there are discrepancies. Assuming KC dependent added mass coefficients, and adding a drag term in the FNV model, as is done in Morison's equation, do not explain the discrepancies. A distinct run-up at the rear of the cylinder is observed in the experiments. A 2D NavierStokes simulation is carried out, and the resulting pressure, due to flow separation, is shown to qualitatively explain the local rear run-up.

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Section: Introductionmentioning

confidence: 99%

Higher harmonic wave loads on a vertical cylinder in finite water depth

Kristiansen

Faltinsen

2017

J. Fluid Mech.

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“…Paulsen (2013) studied higher harmonic loads numerically and compared the obtained results with third order perturbation theories from Faltinsen (1993) and Malenica and Molin (1995). The study by Paulsen (2013) also compared results with the Morison equation with an additional term proposed by Rainey (1989).…”

Section: Higher Harmonic Forcesmentioning

confidence: 99%

Bottom Fixed Substructure Analysis, Model Testing and Design for Harsh Environment

2016

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The aim of this chapter is to study the various hydrodynamic loads important for the design process of offshore wind turbines foundations. A numerical study on weakly non-linear waves was conducted, using the commercial code StarCCMCC. Open-source codes OpenFoam and OceanWave3D were used for the simulation of breaking waves. Existing analytical and empirical formulations, and the results and conclusions from the current numerical study are presented.

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“…Study that obtained 2nd order diffraction wave force acting on a vertical circular cylinder that is fixed to the bottom was performed by Molin & Marison (1986) and Eatock Taylor & Hung (1987). Furthermore, Malenica & Molin (1995) calculated even till the 3rd order at a high-frequency Diffraction wave force. In this study, the 2 nd order hydrodynamic force due to not the diffraction wave force performed in previous studies, but the heave motion of the cylinder, was calculated for the upper surface of the vertical circular cylinder with the top of it to be cut.…”

Section: Introductionmentioning

confidence: 99%

“…However, 2 nd order radiation force due to the motion of a body have not been researched yet. For the 2 nd order radiation wave force calculated in this study, the 2 nd order velocity potential was calculated by using the Green's function integral equation and eigenfunction expansions presented in Malenica & Molin (1995) and Chau & Eatock Taylor (1992). The results were graphically presented on the 2 nd order force and heaving frequency by varying the ratio of the height of the cylinder and the distance of the free * water surface.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Second Order Effect Induced by a Forced Heaving

Kim¹,

Kwon²

2016

Journal of Advanced Research in Ocean Engineering

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In this paper, the 2 nd order hydrodynamic force effect of heaving submerged circular cylinder is considered, with the linear potential theory. Boundary value problem (BVP) is expanded up to the 2 nd order by using of the perturbation method and the 2 nd order velocity potential is calculated by means of integral equation technique using the classical Green's function expressed in cylindrical coordinates. The method of solving BVP is based on eigenfunction expansions. With different cylinder heights and heaving frequencies, graphical results are presented. As a result of the study, the cause of oscillatory force pattern is analyzed with the occurrence of negative added mass when a top of the cylinder gets closer to the free surface.

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Third-harmonic wave diffraction by a vertical cylinder

Cited by 153 publications

References 6 publications

Higher harmonic wave loads on a vertical cylinder in finite water depth

Higher harmonic wave loads on a vertical cylinder in finite water depth

Bottom Fixed Substructure Analysis, Model Testing and Design for Harsh Environment

Second Order Effect Induced by a Forced Heaving

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