Development and validation of harmonic wave group single-run procedure for RAO with comparison to regular wave and transient wave group procedures using URANS

Mousaviraad, Maysam; Carrica, Pablo M.; Stern, Frederick

doi:10.1016/j.oceaneng.2010.01.001

Cited by 27 publications

(9 citation statements)

References 12 publications

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“…They also carried out seakeeping simulations at both full and model scale along with manoeuvring calculations for DTMB 5415 at full-scale. Mousaviraad et al (2010) obtained heave and pitch response amplitudes and phases of the DTMB 5512 model in head seas using regular wave and transient wave group procedures. Following this, Simonsen and Stern (2010) performed CFD RANS simulations to obtain the heave and pitch motions and added resistance for the KCS model, presenting it at the Gothenburg 2010 CFD workshop.…”

Section: Introductionmentioning

confidence: 99%

Full-scale unsteady RANS CFD simulations of ship behaviour and performance in head seas due to slow steaming

et al. 2015

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It is critical to be able to estimate a ship׳s response to waves, since the resulting added resistance and loss of speed may cause delays or course alterations, with consequent financial repercussions. Slow steaming has recently become a popular approach for commercial vessels, as a way of reducing fuel consumption, and therefore operating costs, in the current economic and regulatory climate. Traditional methods for the study of ship motions are based on potential flow theory and cannot incorporate viscous effects. Fortunately, unsteady Reynolds-Averaged Navier–Stokes computations are capable of incorporating both viscous and rotational effects in the flow and free surface waves. The key objective of this study is to perform a fully nonlinear unsteady RANS simulation to predict the ship motions and added resistance of a full scale KRISO Container Ship model, and to estimate the increase in effective power and fuel consumption due to its operation in waves. The analyses are performed at design and slow steaming speeds, covering a range of regular head waves, using a commercial RANS solver. The results are validated against available experimental data and are found to be in good agreement with the experiments. Also, the results are compared to those from potential theory

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Section: Introductionmentioning

confidence: 99%

Full-scale unsteady RANS CFD simulations of ship behaviour and performance in head seas due to slow steaming

et al. 2015

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“…Contento (2000) used a 2-D numerical wave tank, which was based on the BEM technique, to simulate the nonlinear motions of arbitrary shaped bodies in order to develop improved seakeeping techniques. Mousaviraad et al (2010) developed a harmonic group single run seakeeping procedure, which was solved using a general purpose unsteady Reynolds averaged Navier-Stokes (URANS) solver. A linear potential solution was specified at the input boundary in order to generate linear input waves.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of linear water waves and wave–structure interaction

2012

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Publication InformationFinnegan, W,Goggins, J (2012) 'Numerical simulation of linear water waves and wave-structure interaction'. Ocean Engineering, 43 :23-31. Abstract:One of the main stages in the design of wave energy converters (WEC's) is the numerical modelling of a given converter. In this paper, the numerical simulation of both linear deep water waves and linear waves for the finite depth case are explored using computational fluid dynamics (CFD), to aid in this design stage. The CFD software package described in this paper is the commercial finite volume package ANSYS CFX (Release 12.1). The results of parametric studies, which were performed in order to optimise the CFD model, are detailed and a guide to creating a model that produces the desired waves is presented. The model was validated in two ways: (a) the wave created was compared to wavemaker theory (WMT) and (b) the water particle velocity and elevation of the wave was compared to linear, Airy, wave theory (LWT) for deep water waves. It was also found that wave generation in ANSYS CFX using a flap-type wavemaker was restricted to a low normalised wavenumber, k 0 h. In order to increase this restriction, the hinge of the wavemaker was raised and, with this alteration, it is possible to generate deep water linear waves. A case study of a real world application of wave-structure interaction, employing this methodology, is also explored.

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“…As regards evaluation of nonlinear responses in large-amplitude waves, there can be several approaches for solution of this nonlinear problem: (1) a second-order frequency-domain solution based on perturbation theory (Faltinsen 1990;Chakrabarti 1990), (2) a mixed Eulerian-Lagrangian (MEL) approach which was originally developed by Longuet-Higgins and Cokelet (1976) for 2D nonlinear wave studies and subsequently followed up for wave-structure interactions (e.g. Beck 1994;Ferrant 1996) and (3) application of Reynolds-averaged NavierStokes equation (RANSE)-based CFD solvers (Mousaviraad et al 2010;Bunnik et al 2010). The latter two methods can in principle be applied to study extreme wave-structure interaction involving steep nonlinear waves.…”

Section: Introductionmentioning

confidence: 99%

Time-domain simulation of large-amplitude wave–structure interactions by a 3D numerical tank approach

Ganesan

Sen

2015

J. Ocean Eng. Mar. Energy

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A time-domain 3D Rankine panel method based on a simplified variant of the mixed Eulerian-Lagrangian scheme under certain approximations is developed for studying steep nonlinear waves interacting with practical ship and offshore configurations at zero speed. Appropriate techniques have been developed that enable the method to produce very long-duration simulation results. Two levels of time-domain computations are performed: (1) a fully linear formulation where all external forces are computed on the mean wetted surface, and (2) an approximate nonlinear computation where the hydrodynamics interaction forces (diffraction and radiation forces) are determined on the mean surface and the forces arising from the incident steep waves and hydrostatic restoring forces are determined based upon the exact wetted surface under the nonlinear incident wave. Numerical computations for three practical marine structures, the barge, the S175 hull, and the semisubmersible are presented. The linear computations for which very longduration simulations are achievable from the present method are validated against results from other available methods. As the method is developed for stationary floating bodies undergoing oscillation about their mean location, it cannot be applied for a fully unrestrained body which can freely drift. In absence of physical restraints, the approximate nonlinear calculation requires imposition of artificial constraints partially or fully restraining the horizontal motions. Very long-duration simulations under the influence of steep nonlinear large-amplitude waves for all the three structures considered could be achieved. Comparative studies between different force and motion components in large-amplitude waves from linear and the approximate nonlinear computations are made to bring out the influence of the incident wave nonlinearities on these structures. It is found that the nonlinearities of the forces and motions are strongly dependent on the above water hull geometry. Compared to a small water-plane area hull (the semisubmersible), or a wall-sided hull (the barge), a flared hull (S175) results in pronounced nonlinear features in the forces and motion time-histories.

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Development and validation of harmonic wave group single-run procedure for RAO with comparison to regular wave and transient wave group procedures using URANS

Cited by 27 publications

References 12 publications

Full-scale unsteady RANS CFD simulations of ship behaviour and performance in head seas due to slow steaming

Full-scale unsteady RANS CFD simulations of ship behaviour and performance in head seas due to slow steaming

Numerical simulation of linear water waves and wave–structure interaction

Time-domain simulation of large-amplitude wave–structure interactions by a 3D numerical tank approach

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