Numerical investigation of the behaviour and performance of ships advancing through restricted shallow waters

Terziev, Momchil; Tezdogan, Tahsin; Oğuz, Elif; Gourlay, Tim; Demirel, Yiğit Kemal; Incecik, Atilla

doi:10.1016/j.jfluidstructs.2017.10.003

Cited by 76 publications

(51 citation statements)

References 30 publications

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“…The Grid Convergence Index (GCI) method based on Richardson's extrapolation [28] was used to estimate the numerical uncertainties. It is of note that, although the GCI method was firstly proposed for spatial convergence studies, it can also be used for a temporal convergence study, as similarly used by Tezdogan et al [29] and Terziev et al [30].…”

Section: Verificationmentioning

confidence: 99%

Validation of the CFD approach for modelling roughness effect on ship resistance

et al. 2020

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Recently, there have been active efforts to investigate the effect of hull roughness on ship resistance using Computational Fluid Dynamics (CFD). Although, several studies demonstrated that the roughness modelling in the CFD simulations can precisely predict the increase in frictional resistance due to the surface roughness, the experimental validations have been made only for flat plates which have zero pressure gradient. This means that the validations cannot necessarily guarantee the validity of this method for other ship resistance components besides the frictional resistance. Therefore, it is worth to demonstrate the validity of the roughness modelling in CFD on the total resistance of a 3D hull. In this study, CFD models of a towed flat plate and a KRISO Container Ship (KCS) model were developed. In order to simulate the roughness effect in the turbulent boundary layer, a previously determined roughness function of a sand-grain surface was employed in the wall-function of the CFD model. Then the result of the CFD simulations was compared with the experimental data. The result showed a good agreement suggesting that the CFD approach can precisely predict the roughness effect on the total resistance of the 3D hull. Finally, the roughness effects on the individual ship resistance components were investigated. Recently, the use of Computational Fluid Dynamics (CFD) is considered as an effective alternative to improve these shortcomings [17]. The merit of using CFD is that the distribution of the local friction velocity, , is dynamically computed for each discretised cell, and therefore the dynamically varying roughness Reynolds number, + , and corresponding roughness function, + , can be considered in the computation. The 3D effects can also be taken into account, and the simulations are free from the scale effects if they are modelled in full-scale. Correspondingly, there have been increasing number of studies utilising CFD modelling to predict the effect of surface roughness on ship resistance [16, 18-20] and propeller performance [21, 22], as well as ship self-propulsion characteristics [23]. These recent studies suggest that the hull roughness does not only increase the ship frictional resistance but also affects the viscous pressure resistance and the wave making resistance.

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Section: Verificationmentioning

confidence: 99%

Validation of the CFD approach for modelling roughness effect on ship resistance

et al. 2020

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“…Observations on Figure 15 may also help to explain the model behaviour at that speed and blockage ratio. Terziev, et al (2018) presented a numerical study on the DTC container ship in shallow water in order to investigate the sinkage, trim and resistance of ships advancing through restricted shallow water in varying channel cross sections and ship speeds. The authors used Computational Fluid Dynamics (CFD), the Slender-Body theory and various empirical methods to calculate the trim and squat of a containership advancing through different channel geometries.…”

Section: Fnhmentioning

confidence: 99%

Experimental analysis of the squat of ships advancing through the New Suez Canal

et al. 2019

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As a ship travels forward, squat of the ship may occur due to an increase in sinkage and trim. Squat is a crucial factor that restricts ship navigation in shallow water. A new division of the Suez Canal, the New Suez Canal, recently opened for international navigation. It is important to obtain accurate prediction data for ship squat to minimise the risk of grounding in this canal.To provide guidance for shipping in canals a series of experiments was conducted on a model scale of the Kriso Container Ship (KCS). The squat of the KCS was examined by measuring its sinkage and trim. A wide range of water depth to ship draft ratios at various ship speeds was investigated. Additionally, the blockage effect was studied by varying the canal width, and deep water tests were performed. The results indicated that for Froude's number based on depth (Fnh) below 0.4, measured squat value do not change with either Fnh or depth to draft ratio (H/T). The squat increases with H/T values for Froude numbers higher than 0.4. Moreover, a canal with reduced width had a negligible effect on squat, suggesting that the next segment of the Suez Canal can be built to a narrower width.

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“…The indirect methods have been preferred by researchers to the direct methods since the indirect methods are generally simpler and more economical compare to the direct methods. Accordingly, there have been a large number of experimental studies to acquire roughness functions and the corresponding roughness Reynolds number, + , using the indirect methods derived by Granville (1958;1982;1987), including local method with displacement thickness (Schultz and Swain, 1999;Flack et al, 2005;Schultz et al, 2015), local method without displacement thickness (Karlsson, 1978), overall method (Schultz and Myers, 2003;Schultz, 2004;Shapiro, 2004;Demirel, 2015;Demirel et al 2017a) or rotating disk method (Schultz and Myers, 2003;Holm et al, 2004). Schultz and Myers (2003) further concluded that the roughness functions obtained from the different indirect methods can bring a good agreement with the results obtained from the direct method.…”

Section: Introductionmentioning

confidence: 99%

An investigation into the effect of biofouling on the ship hydrodynamic characteristics using CFD

2019

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To reduce the fuel consumption and greenhouse gas emissions of ships, it is necessary to understand the ship resistance. In this context, understanding the effect of surface roughness on the frictional resistance is of particular importance since the skin friction, which often takes a large portion in ship drag, increases with surface roughness. Although a large number of studies have been carried out since the age of William Froude, understanding the roughness effect is yet challenging due to its unique feature in scaling. In this study, a Computational Fluid Dynamics (CFD) based unsteady Reynolds Averaged Navier-Stokes (RANS) resistance simulation model was developed to predict the effect of barnacle fouling mainly on the resistance and hull wake characteristics of the full-scale KRISO container ship (KCS) hull. Initially, a roughness function model was employed in the wallfunction of the CFD software to represent the surface conditions of barnacle fouling. A validation study was carried out involving the model-scale flat plate simulation, and then the same approach was applied in full-scale flat plate simulation and full-scale 3D KCS hull simulation for predicting the effect of barnacle fouling. The increase in frictional resistance due to the different fouling conditions were predicted and compared with the results obtained using the boundary layer similarity law analysis of Granville. Also, a further investigation of the roughness effect on the residuary resistance, viscous pressure resistance and wave making resistance was carried out. Finally, the roughness effect on the wave profile, pressure distribution along the hull, velocity distribution around the hull and wake flows were examined.

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Numerical investigation of the behaviour and performance of ships advancing through restricted shallow waters

Cited by 76 publications

References 30 publications

Validation of the CFD approach for modelling roughness effect on ship resistance

Validation of the CFD approach for modelling roughness effect on ship resistance

Experimental analysis of the squat of ships advancing through the New Suez Canal

An investigation into the effect of biofouling on the ship hydrodynamic characteristics using CFD

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