Numerical Study of Density Ratio Influence on Global Wave Shapes Before Impact

Étienne, Stéphane; Scolan, Yves-Marie; Brosset, L.

doi:10.1115/omae2018-78624

Cited by 4 publications

(9 citation statements)

References 6 publications

(13 reference statements)

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“…28. That is, we consider the simulation of a large gas-pocket impact (LGPI) [9] at scale s = 5, resulting in the impact of a wave of length λ = 4m. Here we are interested in resolving the most unstable wavelength λ KH .…”

Section: Breaking Wave Impactmentioning

confidence: 99%

A sharp, structure preserving two-velocity model for two-phase flow

Remmerswaal¹,

Veldman²

2022

Preprint

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The numerical modelling of convection dominated high density ratio two-phase flow poses several challenges, amongst which is resolving the relatively thin shear layer at the interface. To this end we propose a sharp discretisation of the two-velocity model of the two-phase Navier-Stokes equations. This results in the ability to model the shear layer, rather than resolving it, by allowing for a velocity discontinuity in the direction(s) tangential to the interface.In a previous paper (Remmerswaal and Veldman (2022), arXiv:2209.14934) we have discussed the transport of mass and momentum, where the two fluids were not yet coupled. In this paper an implicit coupling of the two fluids is proposed, which imposes continuity of the velocity field in the interface normal direction. The coupling is included in the pressure Poisson problem, and is discretised using a multidimensional generalisation of the ghost fluid method. Furthermore, a discretisation of the diffusive forces is proposed, which leads to recovering the continuous one-velocity solution as the interface shear layer is resolved.The proposed two-velocity formulation is validated and compared to our one-velocity formulation, where we consider a multitude of two-phase flow problems. It is demonstrated that the proposed two-velocity model is able to consistently, and sharply, approximate solutions to the inviscid Euler equations, where velocity discontinuities appear analytically as well. Furthermore, the proposed two-velocity model is shown to accurately model the interface shear layer in viscous problems, and it is successfully applied to the simulation of breaking waves where the model was used to sharply capture free surface instabilities.

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Section: Breaking Wave Impactmentioning

confidence: 99%

A sharp, structure preserving two-velocity model for two-phase flow

Remmerswaal¹,

Veldman²

2022

Preprint

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“…Finally we consider a high Reynolds number test case for which resolving the interface layer is too expensive. We simulate a smoothed dam break which results in a large gas-pocket impact [3]. In fig.…”

Section: Large Gas-pocket Impactmentioning

confidence: 99%

“…Numerical simulations can facilitate in the understanding of the physics underlying the obeserved variability in impact pressures during breaking wave impacts [3]. One of the mechanisms deemed responsible for pressure variability is the development of free surface instabilities at the wave crest.…”

Section: Introductionmentioning

confidence: 99%

Numerical Modeling Of Two-Phase Flow With Contact Discontinuities

Remmerswaal

Veldman

2021

14th WCCM-ECCOMAS Congress

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When simulating high Reynolds number two-phase flow, boundary layers develop at the interface, which are much thinner compared to the capillary length-scales that are of interest. Resolving such an interface layer is expensive and therefore it is often not resolved in a simulation. Numerically such an underresolved interface layer results in a velocity discontinuity tangential to the interface. We propose to include such tangential velocity discontinuities in our numerical model. This results in a sharp two-fluid model for two-phase flow, where only the interface-normal component of the velocity field is smooth. This condition is implicitly enforced via a new jump condition on the pressure gradient, which we discretize using a multidimensional variant of the ghost fluid method [6]. Results are shown of breaking waves [2] as well as (breaking) waves impacting a solid wall [3] where we compare to state-of-the-art methods [3, 4]. We show that our proposed method is able to accurately simulate high Reynolds number two-phase flow without the need for resolving, or artificially thickening, of the interface layer.

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“…26 Nonetheless, the gas phase should not be neglected, especially when the flow separates near the wave crest. 50 Furthermore, the inertia of the wave tip is small and consequently it is pushed upward where it can eventually be blown off the wave crest. 46,49 Compressible multiphase simulations are required to capture this effect.…”

Section: Introductionmentioning

confidence: 99%

“…26, 51,52 However, the simulations are often not able to capture the development of instabilities on the wave crest. 24,26,50,53 The source of impact pressure variability in repeated wave impact experiments is thought to be the instability development on the wave crest. However, the mechanism that is responsible for the formation of these instabilities is still largely unknown.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of wave tip variability of impacting waves

et al. 2020

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52 peatable and is used to model and scale the pressure of 53 wave impact experiments. 9,10,14-16 In recent years, the 54 study of liquid sloshing 17-21 and slamming on both wave 55 energy converters 22-24 and floating offshore structures 3 56 has received considerable attention. The peak impact 57 pressure is especially relevant in these applications. 3,4 58 A number of reviews have been published both on 59 extreme wave impact events and sloshing. For exam-60 ple, the effect of liquid sloshing impacts has been thor-61 oughly reviewed by Ibrahim 25. A detailed review of wa-62 ter wave impacts on vertical walls is presented by Pere-63 grine 4 , whereas Dias and Ghidaglia 26 present a detailed 64 review on slamming. The impact of a wave can be di-65 vided into several elementary loading processes, such as 66 the direct impact, the jet deflection, and the compres-67 sion of the entrapped or escaping gas. 20 Different types 68 of wave impact can be defined by a combination of el-69 ementary loading processes. The classification of wave 70 impact type depends on the wave shape prior to impact, 71 which is either classified as a slosh, a flip-through, a gas 72 pocket, or an aerated type of wave impact. 4,7,27 For ex-73 ample, the flip-through wave impact has been studied 74 in detail with and without hydro-elasticity. 28,29 The ef-75 fect of hydro-elasticity is relevant for all wave impact 76 types. 30 The flip-through wave impact only occurs for a 77 limited parameter space. 4 On the other hand, the impact 78 of a plunging breaking wave occurs for a wider parameter 79 space and often results in a gas pocket type wave impact. 80 The impact type can easily be identified, but scaling of 81 wave impacts from small-scale to large-scale experiments 82 is not straightforward.

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Numerical Study of Density Ratio Influence on Global Wave Shapes Before Impact

Cited by 4 publications

References 6 publications

A sharp, structure preserving two-velocity model for two-phase flow

A sharp, structure preserving two-velocity model for two-phase flow

Numerical Modeling Of Two-Phase Flow With Contact Discontinuities

Experimental investigation of wave tip variability of impacting waves

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