Review and comparison of methods to model ship hull roughness

Andersson, Jennie; Oliveira, Dinis; Yeginbayeva, Irma; Leer-Andersen, Michael; Bensow, Rickard

doi:10.1016/j.apor.2020.102119

Cited by 46 publications

(26 citation statements)

References 19 publications

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“…This fuel cell was tested with three different cathode configurations [8]. As noted in [31], this roughness ε (FC) is not a real measurable physical characteristic of the surface of the used material for conduits (on the contrary for pipes ε (p) can be measured or at least estimated accurately [32][33][34][35][36][37]).…”

Section: Of 12mentioning

confidence: 99%

Air-Forced Flow in Proton Exchange Membrane Fuel Cells: Calculation of Fan-Induced Friction in Open-Cathode Conduits with Virtual Roughness

Brkić

Praks

2020

Processes

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Measurements of pressure drop during experiments with fan-induced air flow in the open-cathode proton exchange membrane fuel cells (PEMFCs) show that flow friction in its open-cathode side follows logarithmic law similar to Colebrook’s model for flow through pipes. The stable symbolic regression model for both laminar and turbulent flow presented in this article correlates air flow and pressure drop as a function of the variable flow friction factor which further depends on the Reynolds number and the virtual roughness. To follow the measured data, virtual inner roughness related to the mesh of conduits of fuel cell used in the mentioned experiment is 0.03086, whereas for pipes, real physical roughness of their inner pipe surface goes practically from 0 to 0.05. Numerical experiments indicate that the novel approximation of the Wright-ω function reduced the computational time from half of a minute to fragments of a second. The relative error of the estimated friction flow factor is less than 0.5%.

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Section: Of 12mentioning

confidence: 99%

Air-Forced Flow in Proton Exchange Membrane Fuel Cells: Calculation of Fan-Induced Friction in Open-Cathode Conduits with Virtual Roughness

Brkić

Praks

2020

Processes

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“…A standard curve can be constructed from a set of generic roughness function equations such as those given by Cebeci and Bradshaw ( 1977 ) as noted by Andersson et al. ( 2020 ). According to Hunsucker ( 2016 ), Ligrani and Moffat ( 1986 ) gives an expression for the Nikuradse-type roughness function which takes the form: where B N and B 1 are taken as ∼ 8.5 and 5.0 respectively, and where the value of G depends on the flow regime.…”

Section: Methodsmentioning

confidence: 99%

“…Colebrook’s formula, most commonly used in the form of Equation 11 (Andersson et al. 2020 ), applies to all flow conditions: …”

Section: Methodsmentioning

confidence: 99%

“…Various authors have developed expressions for uniformly distributed roughness functions and compared them with Nikuradse's data. A standard curve can be constructed from a set of generic roughness function equations such as those given by Cebeci and Bradshaw (1977) as noted by Andersson et al (2020). According to Hunsucker (2016), Ligrani and Moffat (1986) gives an expression for the Nikuradse-type roughness function which takes the form:…”

Section: Similarity Law Analysismentioning

confidence: 99%

“…Colebrook (1939) investigated irregular surface roughness such as that of corroded metal pipes and derived a theoretical formula for flow in the transitional region between smooth and fully rough flow regimes that differs from Nikuradse's results. Colebrook's formula, most commonly used in the form of Equation 11 (Andersson et al 2020), applies to all flow conditions:…”

Section: Similarity Law Analysismentioning

confidence: 99%

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A rapid benchtop method to assess biofilm on marine fouling control coatings

Dennington

Jackson

Finnie³

et al. 2021

Biofouling

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A rapid benchtop method to measure the torque associated with minidiscs rotating in water using a sensitive analytical rheometer has been used to monitor the drag caused by marine fouling on coated discs. The method was calibrated using sandpaper surfaces of known roughness. Minidiscs coated with commercial fouling control coatings, plus an inactive control, were exposed in an estuarine harbour. After 176 days the drag on the fouling control-coated discs, expressed as a moment coefficient, was between 73% and 90% less than the drag on the control coating. The method has potential use as a screen for novel antifouling and drag reducing coatings and surfaces. Roughness functions derived using Granville's indirect similarity law are similar to patterns found in the general hydrodynamics literature, and so rotational minidisc results can be considered with reference to other fouling drag datasets.

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