A compressible two-phase flow model for pressure oscillations in air entrapments following green water impact events on ships

Eijk, Martin van; Wellens, Peter

doi:10.3233/isp-200278

Cited by 6 publications

(6 citation statements)

References 25 publications

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“…The in-house CFD solver that has been used is called EVA [40][41][42] and developed with a focus on extreme fluid-structure interaction (FSI). EVA is a multiphase flow solver based on the 2D Navier-Stokes equations for the motion of a mixed fluid.…”

Section: Case Descriptionmentioning

confidence: 99%

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Multi-fidelity Kriging extrapolation together with CFD for the design of the cross-section of a falling lifeboat

Wenink,

van der Eijk,

Yorke-Smith

et al. 2023

ISP

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Surrogate modelling techniques such as Kriging are a popular means for cheaply emulating the response of expensive Computational Fluid Dynamics (CFD) simulations. These surrogate models are often used for exploring a parameterised design space and identifying optimal designs. Multi-fidelity Kriging extends the methodology to incorporate data of variable accuracy and costs to create a more effective surrogate. This work recognises that the grid convergence property of CFD solvers is currently an unused source of information and presents a novel method that, by leveraging the data structure implied by grid convergence, could further improve the performance of the surrogate model and the corresponding optimisation process. Grid convergence states that the simulation solution converges to the true simulation solution as the numerical grid is refined. The proposed method is tested with realistic multi-fidelity data acquired with CFD simulations. The performance of the surrogate model is comparable to an existing method, and likely more robust. More research is needed to explore the full potential of the proposed method. Code has been made available online at https://github.com/robertwenink/MFK-Extrapolation.

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Section: Case Descriptionmentioning

confidence: 99%

“…Examples of extreme FSI are found when waves impact with structures [2,29,42,44,45]. Note that when waves are concerned, simulations benefit from Generating Absorbing Boundary Conditions [5,6], both in terms of accuracy and of computing time.…”

Section: Case Descriptionmentioning

confidence: 99%

Multi-fidelity Kriging extrapolation together with CFD for the design of the cross-section of a falling lifeboat

Wenink,

van der Eijk,

Yorke-Smith

et al. 2023

ISP

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“…( 3). At the cell faces the density and viscosity are calculated by cell-weighted averaging (Van Der Eijk and Wellens [22]). Velocities near and above the free surface are not solved for in the one-phase approach.…”

Section: Discretisation Of the Navier-stokes Equationsmentioning

confidence: 99%

“…The numerical method ComFLOW has been under development since Fekken et al [8]. Over the last few years, research is done to improve the description of violent flow phenomena which are both highly non-linear and highly dispersive (Gerrits [10], Kleefsman et al [13], Wemmenhove [29], Van Der Eijk and Wellens [22]). ComFLOW is based on the Navier-Stokes equations for the motion of an aggregated fluid with varying properties.…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical assessment of vertical accelerations during bow re-entry of a RIB in irregular waves

Eijk

Wellens

2021

ISP

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This paper presents the comparison of a self-conducted towing tank experiment with the simulation results of a calibrated state-of-the-art strip-theory method and a first-principles numerical method. The experiment concerns a Rigid Inflatable Boat (RIB) in moderate-to-high irregular waves. These waves result in bow emersion events of the RIB. Bow re-entry induces vertical accelerations which, in reality, can lead to severe injuries and structural damage. State-of-the-art methods for predicting the vertical acceleration levels are based on assumptions, require calibration and are often limited in application range. We demonstrate how the vertical acceleration as a function of time is found from a 3D numerical method based on the Navier–Stokes equations, employing the Volume of Fluid (VoF) method for the free surface, without any further assumptions or limitations. 2D+t strip theory methods like Fastship are based on the mechanics of wedges falling in water. The 3D numerical method that is part of the software ComFLOW is compared to previous research on falling wedges in 2D to investigate the effect of air and to find suitable grid distances for the 3D simulation of the RIB. The 3D RIB simulations are compared to Fastship and the experiment. With respect to the experiment, the ComFLOW simulations show a slight underestimation of the levels of heave and pitch. The underestimation of Fastship is larger. The prediction of acceleration in ComFLOW is hardly different from the experiment and a significant improvement with respect to Fastship. ComFLOW is demonstrated to predict acceleration levels better than before, which creates opportunities for using it in seakeeping optimization and for the improvement of methods like Fastship. The properties of the RIB and the experiment are available as open data at Wellens (2020).

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“…The externally added interaction is solved using the Crank Nicolson scheme in the reduced order model and in EVA. A detailed description and validation of the CFD flow solver EVA is given in [23]. Both codes are used in this paper to investigate the effects of fluid-structure interaction for a wave impact.…”

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confidence: 99%

A reduced order model for FSI of tank walls subject to wave impacts during sloshing

Bos

Eijk

Besten

et al. 2022

ISP

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Loads due to wave impacts are a limiting factor in the design of liquefied natural gas (LNG) tankers and their insulation. The current methodology considers the load independent from the response of the tank. Better tanks can be designed by knowing the effect of the interaction between the wave loads and the response, however predicting these effects is computationally expensive. In this paper a new application of the non-hydrostatic shallow water equations are presented, namely as a reduced order model (ROM) for fluid structure interaction for wave impacts. Our ROM is compared to a high fidelity model. The proposed ROM is fast and accurately predicts the total impulse and added mass, and therefore the general behaviour of the structure during the free vibration phase. It does however not always accurately predict the maximum force. It is therefore considered an appropriate tool for a first screening of the loads for which fluid-structure interaction is important, after which a more accurate method can be used to evaluate the most interesting cases. A sensitivity study is performed for various impact angles and velocities, showing that the importance of fluid structure interaction depends highly on the specific situation.

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A compressible two-phase flow model for pressure oscillations in air entrapments following green water impact events on ships

Cited by 6 publications

References 25 publications

Multi-fidelity Kriging extrapolation together with CFD for the design of the cross-section of a falling lifeboat

Multi-fidelity Kriging extrapolation together with CFD for the design of the cross-section of a falling lifeboat

Experimental and numerical assessment of vertical accelerations during bow re-entry of a RIB in irregular waves

A reduced order model for FSI of tank walls subject to wave impacts during sloshing

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