On the drifting speed of floating bodies in waves

Tanizawa, Katsuji; Minami, Makiko; Imoto, Yasuji

doi:10.2534/jjasnaoe1968.2001.190_151

Cited by 6 publications

(4 citation statements)

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“…The amplification factors u O /u S of these large boxes initially decrease somewhat with increasing steepness for low values of steepness, but then reach constant values as steepness increases. This is consistent with what has been found in the experiments conducted by Huang et al (2011), Huang & Law (2013), He et al (2016) and Tanizawa et al (2002). To be more specific, in the experiments of Huang et al (2011) for 'small' floating objects (l/λ = 13 %-16 %), these authors found that object drift is enhanced more as wave steepness increases and that the amplification factor u O /u S behaved in a similar fashion as presented here.…”

Section: Effect Of Wave Steepness (Category Iii)supporting

confidence: 91%

“…Enhanced drift was found for all shapes, and objects with a larger submergence depth experienced a greater increase in drift regardless of shape. The studies of Tanizawa, Minami & Imoto (2002) and He, Ren & Qiu (2016) showed that small objects behave like Lagrangian particles, following the Stokes drift, while large objects drift faster than Lagrangian particles with wave reflection off the object evident.…”

Section: Introductionmentioning

confidence: 99%

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Surface gravity wave-induced drift of floating objects in the diffraction regime

Xiao,

Calvert,

Yan

et al. 2024

J. Fluid Mech.

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Floating objects will drift due to the action of surface gravity waves. This drift will depart from that of a perfect Lagrangian tracer due to both viscous effects (non-potential flow) and wave–body interaction (potential flow). We examine the drift of freely floating objects in regular (non-breaking) deep-water wave fields for object sizes that are large enough to cause significant diffraction. Systematic numerical simulations are performed using a hybrid numerical solver, qaleFOAM, which deals with both viscosity and wave–body interaction. For very small objects, the model predicts a wave-induced drift equal to the Stokes drift. For larger objects, the drift is generally greater and increases with object size (we examine object sizes up to $10\,\%$ of the wavelength). The effects of different shapes, sizes and submergence depths and steepnesses are examined. Furthermore, we derive a ‘diffraction-modified Stokes drift’ akin to Stokes (Trans. Camb. Phil. Soc., vol. 8, 1847, pp. 411–455), but based on the combination of incident, diffracted and radiated wave fields, which are based on potential-flow theory and obtained using the boundary element method. This diffraction-modified Stokes drift explains both qualitatively and quantitatively the increase in drift. Generally, round objects do not diffract the wave field significantly and do not experience a significant drift enhancement as a result. For box-shape objects, drift enhancement is greater for larger objects with greater submergence depths (we report an increase of $92\,\%$ for simulations without viscosity and $113\,\%$ with viscosity for a round-cornered box whose size is $10\,\%$ of the wavelength). We identify the specific standing wave pattern that arises near the object because of diffraction as the main cause of the enhanced drift. Viscosity plays a small positive role in the enhanced drift behaviour of large objects, increasing the drift further by approximately $20\,\%$ .

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Section: Effect Of Wave Steepness (Category Iii)supporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Surface gravity wave-induced drift of floating objects in the diffraction regime

Xiao,

Calvert,

Yan

et al. 2024

J. Fluid Mech.

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“…This idea was originally suggested in series of Tanizawa's works [21]. In this paper the procedure given by Tanizawa is borrowed and some implemental issues are explained.…”

Section: Evaluation Of the Wave Forces And Momentsmentioning

confidence: 99%

“…The expression for the second term is stated for two-dimensions in Tanizawa [21]. For the three dimensional case, the equation of the particle acceleration in Fochesato et al [6] can be utilized for the present purpose.…”

Section: Evaluation Of the Wave Forces And Momentsmentioning

confidence: 99%

Development of a Boundary Element Method-based numerical wave tank technique for the prediction of nonlinear wave kinematics and dynamics around offshore structures

Sung

2009

Mesh Reduction Methods

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This paper presents recent accomplishments of the development of the Boundary Element Method (BEM) for nonlinear waves around offshore structures and resulting wave forces. In order to investigate the capability of the present method, the nonlinear diffraction problem of a truncated circular cylinder is simulated. It is found that the present method is fairly accurate for wave forces and run-ups when compared with experimental results and also with other numerical results.

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QALE‐FEM for numerical modelling of non‐linear interaction between 3D moored floating bodies and steep waves

Yan

2008

Numerical Meth Engineering

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This is the accepted version of the paper.This version of the publication may differ from the final published version. applied to 2D floating bodies), the complex unstructured mesh is generated only once at the beginning of calculation and is moved to conform to the motion of boundaries at other time steps by using a robust spring analogy method specially suggested for this kind of problems, avoiding the necessity of high cost remeshing. Permanent repository linkIn order to tackle challenges associated with 3D floating bodies, several new numerical techniques are developed in this paper. These include the technique for moving the mesh near body surfaces, the scheme for calculating velocity on 3D body surfaces and the ISITIMFB-M (Iterative Semi-Implicit Time IntegrationMethod for Floating Bodies -Modified) procedure that is more efficient for dealing with the full coupling between waves and bodies. Using the newly developed techniques and methods, various cases for 3Dfloating bodies with motions of up to 6 degrees of freedom (DoFs) are simulated. These include a SPAR platform, a barge-type floating body and one or two Wigley Hulls in head seas or in oblique waves. For some selected cases, the numerical results are compared with experimental data available in the public domain and satisfactory agreements are achieved. Many results presented in this paper have not been found elsewhere to the best knowledge of the authors.

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On the drifting speed of floating bodies in waves

Cited by 6 publications

References 0 publications

Surface gravity wave-induced drift of floating objects in the diffraction regime

Surface gravity wave-induced drift of floating objects in the diffraction regime

Development of a Boundary Element Method-based numerical wave tank technique for the prediction of nonlinear wave kinematics and dynamics around offshore structures

QALE‐FEM for numerical modelling of non‐linear interaction between 3D moored floating bodies and steep waves

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