Modelling of hull roughness

Speranza, Nicola; Kidd, Barry; Schultz, Michael P.; Viola, Ignazio Maria

doi:10.1016/j.oceaneng.2019.01.033

Cited by 16 publications

(8 citation statements)

References 36 publications

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“…in CFD simulations (Demirel b et al, 2017, Farkas b et al, 2018, Speranza et al, 2019, Song c et al, 2019. The merit of using CFD simulations is that it allows determination of the roughness effect on every resistance component (Song c et al, 2019.…”

Section: Introductionmentioning

confidence: 99%

Impact of biofilm on the ship propulsion characteristics and the speed reduction

et al. 2020

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Ship fuel consumption and the greenhouse gas emissions in the service are affected by various factors, including waves, wind, biofouling, corrosion, confined water. One of the operational measures for the reduction of the fuel consumption is the optimization of the maintenance schedule, but lack of information related to the potential benefits of the application of this measure represents an important barrier. Therefore, the prediction of the impact of biofouling on ship hydrodynamic characteristics is important. In this paper, a numerical model based on Reynolds Averaged Navier-Stokes (RANS) equations, which allows the prediction of the impact of biofilm on the ship propulsion characteristics is proposed. Roughness function models representing surface conditions of biofilm fouling were employed within the wall function of the CFD software. Thereafter, a detail analysis of the impact of biofilm on the propulsion characteristics and the flow around full-scale containership is presented. This study has demonstrated that the occurrence of biofilm should not be ignored and that the presence of biofilm can cause extremely detrimental effects on ship hydrodynamic characteristics. Thus, it is shown that the biofilm can cause a significant increase in delivered power and consequently an increase in fuel consumption or a decrease in ship speed, contradicting the often ignoring of the biofilm presence on the ship hull.

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Section: Introductionmentioning

confidence: 99%

Impact of biofilm on the ship propulsion characteristics and the speed reduction

et al. 2020

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“…The analyses performed for model scale flat plate, full-scale flat plate and full-scale KCS hull. Similar studies focussing on modelling the roughness in CFD can be found in [51,52], [53], [54] and [55].…”

Section: Introductionmentioning

confidence: 71%

A CFD study: Influence of biofouling on a full-scale submarine

Uzun

Sezen

Ozyurt

et al. 2021

Applied Ocean Research

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“…A sensitivity analysis with different fluid speeds and surface roughness was then done employing the flat field. The reproduction of surface roughness is defined through an equivalent sand grain diameter (k s ) [30][31][32][33]. The scaleequipped plate with most promising results in terms of drag reduction in the first analysis was considered as the fixed scale model; in Appendix 3, the model was adopted to relate surface roughness with the sand grain diameter.…”

Section: Effect Of Scale Design and Surface Roughness On Water Dragmentioning

confidence: 99%

Feasibility of using bio-mimicking fish scale textures in LPBF for water drag-reducing surfaces

2023

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In this work, bio-mimicking fish scale textures are produced by LPBF and AlSi7Mg0.6 powder to reduce drag forces on nautical components. For this purpose, a surface texture inspired by the European bass skin was modelled and parametrized. Textures were applied over the external surface of purpose-designed specimens. Additive manufacturing quality of textures was assessed using focus variation microscopy to examine surface roughness as well as geometrical errors. Once the feasibility of producing the desired bio-mimicking surfaces was confirmed, the designed surface patterns were analysed in the computation fluid dynamics modelling environment. The behaviour of the surfaces was characterized in terms of drag force generated over a fixed dimension plate model. The most promising configuration was further investigated in a sensitivity analysis where variations in main stream velocity and in surface roughness are applied. Drag reduction was related to the lowering of the viscous component and was found to be in the order of 1–2%, with respect to a smooth surface, for free stream velocity of 2.5–5 m s−1 and average roughness smaller than the as-built condition. The results confirm that the modelled surfaces can be reproduced with sufficient geometrical fidelity, showing great promise for drag-reducing metallic components produced by additive manufacturing.

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Modelling of hull roughness

Cited by 16 publications

References 36 publications

Impact of biofilm on the ship propulsion characteristics and the speed reduction

Impact of biofilm on the ship propulsion characteristics and the speed reduction

A CFD study: Influence of biofouling on a full-scale submarine

Feasibility of using bio-mimicking fish scale textures in LPBF for water drag-reducing surfaces

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