scholarly journals Experimental and Theoretical Study of the Effect of Hull Roughness on Ship Resistance

2020 ◽  
pp. 1-10 ◽  
Author(s):  
Soonseok Song ◽  
Saishuai Dai ◽  
Yigit Kemal Demirel ◽  
Mehmet Atlar ◽  
Sandy Day ◽  
...  
Keyword(s):  
Flat Plate ◽  
Rough Surface ◽  
Frictional Resistance ◽  
Total Resistance ◽  
Roughness Effect ◽  
Surface Conditions ◽  
Ship Model ◽  
Ship Resistance ◽  
Scaling Procedure ◽  
Similarity Law

Hull roughness increases ship frictional resistance and, thus, results in economic and environmental penalties. Its effect has been prevalently predicted using the similarity law scaling procedure. However, this method has not yet been validated with experimental data using a model ship. This study presents an experimental investigation into the effect of roughness on ship resistance and provides a validation of the similarity law scaling, by using tank testing of a flat plate and a model ship. Both the plate and the ship were tested in smooth and rough surface conditions, respectively. For the rough surface conditions, sand grit (aluminum oxide abrasive powder) was applied on the surfaces of the flat plate and the ship model. The roughness functions of the rough surface were derived by using the results obtained from the flat plate tests. Using the roughness function and the flat plate towing test, frictional resistance was extrapolated to the length of the model ship following the similarity law scaling procedure. The total resistance of the rough ship model was first predicted using the extrapolated frictional resistance and the result of the smooth ship model, and then compared with the results from the rough ship model. The predicted total resistance coefficients for the rough ship model showed a good agreement with the measured total resistance coefficient of the rough ship model, thus proving the validity of using Granville's similarity law scaling to extrapolate the roughness effect on ship resistance. 1. Introduction Roughness of a ship's hull, which is often caused by hull fouling (Townsin 2003) and corrosion (Tezdogan & Demirel 2014), can dramatically increase the ship resistance and hence its fuel consumption and greenhouse gas emissions, as well as the cost associated with dry-docking (Schultz et al. 2011); Granville (1958; 1978). Accordingly, there have been numerous investigations into the roughness effect on ship resistance from the earliest times to the present (e.g., McEntee 1915; Hiraga 1934; Kempf 1937; Benson et al. 1938; Watanabe et al. 1969; Loeb et al. 1984; Lewkowicz & Das 1986; Lewthwaite et al. 1985; Haslbeck & Bohlander 1992; Schultz 1998; Schultz & Swain 1999; Schultz 2002; Schultz 2004; Andrewartha et al. 2010; Schultz et al. 2011; Demirel 2015; Demirel et al. 2017a; Demirel et al. 2019).

Experimental Investigation of Roughness Effect on Ship Resistance Using Flat Plate and Model Towing Tests

2017 ◽  
Vol 61 (02) ◽  
pp. 75-90
Author(s):  
Evangelia D. Kiosidou ◽  
Dimitrios E. Liarokapis ◽  
Georgios D. Tzabiras ◽  
Dimitrios I. Pantelis
Keyword(s):  
Flat Plate ◽  
Resistance Coefficient ◽  
Extrapolation Method ◽  
Total Resistance ◽  
Roughness Effect ◽  
Towing Tank ◽  
Ship Model ◽  
Rough Model ◽  
Smooth Model ◽  
Flow Stimulation

Towing tests on a thin flat plate of 3-mm thickness and on a ship model in smooth and rough condition were performed and extrapolation to ship scale was attempted. A newly designed experimental setup was constructed for the examination of the thin plate. The experiments on smooth flat plate included examination of a series of trip wires for flow stimulation, among which the optimum was 1.3 mm. In rough condition, the plate was covered with sandpapers of 40 and 80 grit. Both calculated roughness functions exhibited Nikuradse behavior, verifying the validity of the experiments. The equivalent sand roughness height was 1.7 times the average sandpaper roughness, as calculated by the Schlichting diagram for sand-roughened plates. Both roughness functions indicated transitionally rough regime, except for the last two data of the rougher sandpaper that lay on the fully rough regime. The results were extrapolated to ship scale using Granville method. Extrapolation of smooth model results in ship scale revealed that the traditional Froude method predicts higher resistance coefficient compared to the International Towing Tank Conference (ITTC) 78 method. Rough model results were extrapolated to ship scale by applying a newly proposed extrapolation method, using Schlichting resistance formula for rough plates as the friction correlation line, according to Froude method and for two length scales, namely the plate and ship length. The two versions of the proposed extrapolation method provided an upper and lower limit for the predicted rough hull total resistance coefficient.

scholarly journals Investigate the Drag Resistance of Antifouling Self-Adhesive Film

2020 ◽  
Vol 77 (2) ◽  
pp. 13-22
Author(s):  
Khor Wei-Hann ◽  
Siow Chee Loon ◽  
Adi Maimun Abdul Malik ◽  
Arifah Ali ◽  
Mohammad Nabil Jainal ◽  
...  
Keyword(s):  
Coefficient Of Friction ◽  
Frictional Resistance ◽  
Percentage Increase ◽  
Ansys Fluent ◽  
Adhesive Film ◽  
Ship Model ◽  
Ship Resistance ◽  
Lack Of Information ◽  
The Coefficient Of Friction ◽  
Rotor Apparatus

Fouling has always been a common issue for ships as fouling drastically increases the surface roughness and ship resistance. The microfiber self-adhesive antifouling film is claimed to be effective up to 5 years and is environmentally friendly. However, there is lack of information about the drag characteristics of the antifouling material. Thus, this project is conducted based on an experimental study to determine the drag characteristics of the surface installed with microfiber self-adhesive antifouling film. The rotor apparatus is used to study the coefficient of friction of the microfiber surface. From the experimental results, a flat plate simulation using ANSYS-Fluent is conducted to further estimate the coefficient of friction up to Reynolds number of 109 and to evaluate the total ship resistance for the Semi-SWATH (fast vessel) and KVLCC (slow trading ships). The results show that the percentage increase in total ship resistance for the KVLCC is about 80%, which is more than the Semi-SWATH of 30%, as frictional resistance has high significance for slow trading ships. The speed drop experienced by the ship model installed with the microfiber antifouling is 2 knots for the KVLCC and 1 knot for the Semi-SWATH if the power remained the same for both models.

The Axial Frictional Resistance of Long Cylinders in Turbulent Flow

1959 ◽  
Vol 3 (03) ◽  
pp. 24-28
Author(s):  
K. Karhan
Keyword(s):  
Turbulent Flow ◽  
Flat Plate ◽  
Frictional Resistance ◽  
The Other ◽  
Ship Model ◽  
Transverse Curvature ◽  
Other Hand ◽  
Length And Area ◽  
Mathematical Relations

In ship-model extrapolation the frictional resistance of the ship surface is generally taken to be equal to that of the flat plate having the same length and area. Experiments carried out at several laboratories with models of different size show dearly that each model should have its own extrapolation curve. In spite of general agreement that this is so, the flat-plate extrapolation curve is still generally used. On the other hand it is not easy to derive mathematical relations for ship-form frictional resistance or to make extensive experiments for this purpose. It is obvious that a first step towards departing from the flat-plate resistance basis should be to study the effect of transverse curvature on frictional resistance.

scholarly journals Impact of biofilm on the resistance characteristics and nominal wake

2019 ◽  
Vol 234 (1) ◽  
pp. 59-75 ◽  
Author(s):  
Andrea Farkas ◽  
Nastia Degiuli ◽  
Ivana Martić
Keyword(s):  
Frictional Resistance ◽  
Total Resistance ◽  
Wall Function ◽  
Scaling Method ◽  
Resistance Increase ◽  
Numerical Assessment ◽  
Commercial Software Package ◽  
Function Models ◽  
The Impact ◽  
Similarity Law

Numerical assessment of the impact of biofilm on the resistance characteristics and nominal wake is carried out within this study. Therefore, roughness function models are implemented within the wall function of the commercial software package. Extensive verification study as well as the estimation of numerical uncertainties in the prediction of the resistance characteristics and nominal wake is made. Furthermore, numerical uncertainties in the prediction of the change in resistance characteristics and nominal wake are assessed as well. Thereafter, validation study is carried out by comparing the obtained increases in the frictional and total resistance with the increases obtained using Granville similarity law scaling method. The significant impact of biofilm on the resistance characteristics as well as on the nominal wake is noted. Thus, total resistance and frictional resistance increase due to the presence of biofilm, while wave resistance decreases, contradicting the classical methods, which consider that only frictional resistance is affected due to the presence of roughness. Furthermore, nominal wake coefficient is increased due to the presence of biofilm, which causes slowdown of the flow.

Experimental Investigation of Roughness Effect on Ship Resistance Using Flat Plate and Model Towing Tests

2017 ◽  
Vol 61 (2) ◽  
pp. 75-90 ◽  
Author(s):  
Evangelia D. Kiosidou ◽  
Dimitrios E. Liarokapis ◽  
Georgios D. Tzabiras ◽  
Dimitrios I. Pantelis
Keyword(s):  
Experimental Investigation ◽  
Flat Plate ◽  
Roughness Effect ◽  
Ship Resistance

scholarly journals Effects of Roughness on Stresses in an Oxide Scale Formed on a Superalloy Substrate

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 479
Author(s):  
Yang Zhao ◽  
Fan Sun ◽  
Peng Jiang ◽  
Yongle Sun
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Residual Stresses ◽  
Oxide Scale ◽  
Rough Surface ◽  
Alumina Scale ◽  
Growth Stress ◽  
Oxide Growth ◽  
Substrate Thickness ◽  
Roughness Effect

The effects of surface roughness on the stresses in an alumina scale formed on a Fecralloy substrate are investigated. Spherical indenters were used to create indents with different radii and depths to represent surface roughness and then the roughness effect was studied comprehensively. It was found that the residual stresses in the alumina scale formed around the rough surface are almost constant and they are dominated by the curvature rather than the depth of the roughness. Oxidation changes the surface roughness. The edge of the indent was sharpened after oxidation and the residual stress there was released presumably due to cracking. The residual stresses in the alumina scale decrease with increase in oxidation time, while the substrate thickness has little effect, given that the substrate is thicker than the alumina scale. Furthermore, the effect of roughness on the oxide growth stress is analysed. This work indicates that the surface roughness should be considered for evaluation of stresses in coatings.

scholarly journals Resistance reduction on trimaran ship model by biopolymer of eel slime

2015 ◽  
Vol 12 (2) ◽  
pp. 95-102
Author(s):  
Y. Yanuar ◽  
G. Gunawan ◽  
M. A. Talahatu ◽  
R. T. Indrawati ◽  
A. Jamaluddin
Keyword(s):  
Drag Reduction ◽  
Frictional Resistance ◽  
Skin Surface ◽  
Fish Skin ◽  
Total Drag ◽  
Towing Tank ◽  
Ship Model ◽  
Resistance Reduction ◽  
Towing Tank Test ◽  
Tank Test

Resistance reduction in ship becomes an important issue to be investigated. Energy consumption and its efficiency are related toward drag reduction. Drag reduction in fluid flow can be obtained by providing polymer additives, coating, surfactants, fiber and special roughness on the surface hull. Fish skin surface coated with biopolymers viscous fluid (slime) is one method in frictional resistance reduction. The aim of this is to understanding the effect of drag reduction using eel slime biopolymer in unsymmetrical trimaran ship model. The Investigation was conducted using towing tank test with variation of velocity. The dimension of trimaran model are L = 2 m, B = 0.20 m and T = 0.065 m. The ship model resistance was precisely measured by a load cell transducer. The comparison of resistance on trimaran ship model coated and uncoated by eel slime are shown on the graph as a function of the total drag coefficient and Froude number. It is discovered the trimaran ship model by eel slime has higher drag reduction compared to trimaran with no eel slime at similar displacement. The result shows the drag reduction about 11 % at Fr 0.35.

scholarly journals Analysis of Effect of Bulbous Bow Shape to Ship Resistance in Catamaran Boat

2018 ◽  
Vol 159 ◽  
pp. 02058
Author(s):  
Deddy Chrismianto ◽  
Kiryanto ◽  
Berlian Arswendo Adietya
Keyword(s):  
Fluid Dynamic ◽  
The Body ◽  
Wave System ◽  
Total Resistance ◽  
Factors Affecting ◽  
Ship Resistance ◽  
Bow Wave ◽  
Main Factors ◽  
The One ◽  
Bulbous Bow

Ship resistance is one of the main factors affecting the design of a ship. Catamaran boat is a ship with small wet surface area that able to reduce drag and improve ship power. Generally, a bulbous bow is implemented to reduce wave resistance because the bulbous shape is believed to attenuate the bow wave system. Additionally, the bulbous bow also tends to reduce viscous resistance. When the flow around the body is smooth, the total ship resistance can be reduced significantly if the optimum bulbous bow is obtained. In this study, the main purpose is to get the bulbous bow shape in catamaran boat which produces the smallest ship resistance by using computational fluid dynamic (CFD). Generating the variation of the bulbous bow shapes apply the one-to-one correspondence of the cross section parameter (ABT) and lateral parameter (ABL). The result of investigation shows that application of bulbous bow on catamaran boat can reduce about 11-13% of total resistance of ship.

Research on the Wing's Thrust of “Wenzhuhai” Ship with Install Wing

2012 ◽  
Vol 462 ◽  
pp. 307-312 ◽  
Author(s):  
Hong Ying Ren ◽  
Pei Ting Sun ◽  
You Tao Zhao ◽  
Lian Zhong Huang ◽  
Hong Ming Wang ◽  
...  
Keyword(s):  
Model Test ◽  
Ship Model ◽  
Ship Resistance ◽  
Examination Result ◽  
Ship Model Test ◽  
Fluent Software

In this paper the resistance of one ship with installing wing and wing’s thrust have been studied in both theory and simulation by fluent software. The influence of ship resistance which from leeway angle and down helm was analyzed on the basis of the examination result of ship model test.

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