Investigation of linear wave action around a truncated cylinder with non-circular cross section

Liu, Jiabin; Guo, Anxin; Fang, Qinghe; Li, Hui; Hu, Hui; Liu, Pengfei

doi:10.1007/s00773-017-0516-0

Cited by 21 publications

(15 citation statements)

References 18 publications

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“…For example, Bhatta and Rahman [11] tackled the diffraction and radiation problems of floating circular cylinders and Yeung [12] obtained the added mass and radiation damping of a vertical cylinder while Chen and Mei [13] addressed floating elliptical cylinders by using the Mathieu function and Williams and Darwiche [14] developed two approximate solutions for the wave radiation by a truncated elliptical cylinder in order to reduce computational efforts. Liu et al and Yu et al [15,16] presented a semi-analytical method to handle the diffraction problem and radiation problem of floating arbitrarily shaped cylinders, respectively. By using the semi-analytical method, they investigated the hydrodynamic behaviour of a triangular cosine-type cylinder and a quasi-elliptical cylinder.…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamic Behaviour of Floating Polygonal Platforms under Wave Action

Park¹,

Wang²

2021

JMSE

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The hydrodynamic behaviour of floating regular polygonal platforms under wave action was studied by conducting parametric studies. Considering triangular, square, hexagonal, and circular platforms of similar size and draft, the results show that their added mass, radiation damping, and RAOs are similar. However, the wave exciting forces are slightly different, particularly the horizontal forces. The polygonal platforms oriented with one of its corners in line with the prevailing wave direction can lead to a reduction in the horizontal force on the platform, a feature that helps in reducing the cost of a mooring system. Moreover, such oriented platforms are able to disperse the waves better in multiple directions and hence will not pose problems for ships or marine vessels passing by the platform on the weather side. Thus, the orientation of a polygonal platform is an important design consideration. From the comparison study among different polygonal platforms, their wave attenuation performances are slightly similar. The hydrodynamic analyses performed herein for the parametric studies were sped up considerably by using a significantly lesser number of Fourier coefficient sets for the series functions that define the velocity potentials when compared to those used by previous researchers in their analytical approaches. The adoption of the radius function defined by cosine-type radial perturbation does not only generate the geometric boundaries of polygonal platforms, but it also simplifies the formulation and quickens the computations.

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Section: Introductionmentioning

confidence: 99%

Hydrodynamic Behaviour of Floating Polygonal Platforms under Wave Action

Park¹,

Wang²

2021

JMSE

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“…To study the influence of the spacing between the caissons, e, we consider the same two caissons deployed with four different spacings, i.e., e/h=0.5, 1.0, 1.5 and 2.0, suffering from incoming waves with =π/6 are studied. In addition, as a comparison, wave diffraction from an individual caisson isolated in open sea is also analytically solved by using the method of [25]. The isolated caisson case is equivalent to the two-caisson case with an extremely large spacing between them, i.e., e/h=∞, that the hydrodynamic interaction is vanishing.…”

Section: Effect Of Spacing Between Caissonsmentioning

confidence: 99%

“…More recently, the linear wave diffraction by a vertical, uniform, surface piercing cylinder with an arbitrary smooth cross-section was analytically solved by Liu, Guo and Li [24], Liu, Guo, Fang, Li, Hu and Liu [25]. The Fourier series method combined with the Galerkin method were used to satisfy the wetted surface body conditions and continuity conditions between adjacent subdomains.…”

Section: Introductionmentioning

confidence: 99%

“…and take (τ=-M,…,0, …, M) and (ζ=0,1, …, L) in Eqs (24). and(25) as well, thus a 2N(2M+1)(L+1)-order complex linear equation matrix is obtained, which can be used to calculate the same number of unknown coefficients the following analytic computations, M=15 and L=8 are taken so as to obtain accurate results.4 Wave excitation forces and momentsThe hydrodynamic pressure in the flow domain is given by the linearized Bernoulli equation, p=-ρ∂Re[(ΦI+ΦD)e -iωt ]/∂t= ρRe[iω(ΦI+ΦD)e -iωt ], where ρ represents the water density. Therefore, the generalized excitation force on cylinder n in Mode j (j=1~6 represent surge, sway, heave, roll, pitch and yaw, respectively) can be calculated from…”

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confidence: 99%

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Wave diffraction from multiple truncated cylinders of arbitrary cross sections

Zheng

Zhang

Liu

et al. 2020

Applied Mathematical Modelling

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Many marine structures are supported by piles or caissons which, from a mathematical point of view, can be assimilated to an array of truncated cylinders of arbitrary cross sections. The focus of this paper is such an array subjected to harmonic waves of small steepness. We develop an analytic method based on linear potential flow theory to solve the diffraction problem and evaluate the excitation forces and moments acting on each cylinder. The water domain is divided into the interior regions below each cylinder and an exterior region extending to infinity in the horizontal plane. A series of eigen-functions are applied to express the velocity potential in each region. The Fourier series method combined with the eigen-function expansion matching method is used to satisfy the wetted surface body conditions and continuity conditions between adjacent regions. The analytic model is validated by comparing its results with numerical modelling results and published data. It is then applied to two truncated cylinders with caisson cross sections, and results are given for the excitation forces and moments on each cylinder for different values of incident wave direction and spacing between the cylinders, and for different configurations.

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“…Vertical cylinders with elliptical cross sections can be adopted as the foundations of some coastal/offshore bridges as well (Wan et al, 2017). A more common shape of the bridge's foundation, however, might be a quasi-elliptical section (Liu et al, 2017;Eidem 2017). For all these marine structures, the radiation problem of a cylinder with different cross-sections is involved in either their operation or installation.…”

Section: Introductionmentioning

confidence: 99%

Wave radiation from a truncated cylinder of arbitrary cross section

et al. 2019

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In this paper, a semi-analytical model for solving wave radiation from a truncated cylinder of arbitrary cross section is presented based on linear potential flow theory. The water domain is divided into the interior domain beneath the cylinder and the exterior domain outside the vertical cylinder column. Radiated spatial potentials in these subdomains are expressed as a series expansion of eigen-functions using the method of separation of variables. The continuity conditions for pressure and velocity are satisfied at the interface of the two domains, where the Fourier series expansion method is employed to deal with the radius function associated terms. Therefore, the unknown coefficients in the radiated potential expressions are determined by means of the eigen-function matching method. Hydrodynamic coefficients of the truncated cylinder are evaluated directly based on the radiated spatial potentials. Case studies on wave radiation from a truncated cylinder with "cosine" and "circular" cross sections show a good agreement between the semi-analytical results of added-mass/radiation damping and numerical ones/published data. The validated semi-analytical model is then adopted to study the hydrodynamic characteristics of truncated cylinders with "circular", "cosine", "elliptical" and "quasi-elliptical" sections. For the latter case, the influence of draft on wave radiation is also investigated.

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Investigation of linear wave action around a truncated cylinder with non-circular cross section

Cited by 21 publications

References 18 publications

Hydrodynamic Behaviour of Floating Polygonal Platforms under Wave Action

Hydrodynamic Behaviour of Floating Polygonal Platforms under Wave Action

Wave diffraction from multiple truncated cylinders of arbitrary cross sections

Wave radiation from a truncated cylinder of arbitrary cross section

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