Study on the total resistance prediction of ship by numerical complete similarity ship model

2011 ◽  
Author(s):  
Haiyan Xie ◽  
Ying Xiong
Keyword(s):  
Total Resistance ◽  
Ship Model ◽  
Resistance Prediction

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.

Surface Ship Total Resistance Prediction Based on a Nonlinear Free Surface Potential Flow Solver and a Reynolds-Averaged Navier-Stokes Viscous Correction

2007 ◽  
Vol 51 (01) ◽  
pp. 47-64
Author(s):  
James C. Huan ◽  
Thomas T. Huang
Keyword(s):  
Free Surface ◽  
Surface Potential ◽  
Potential Flow ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Navier Stokes ◽  
Total Resistance ◽  
Flow Solver ◽  
Resistance Prediction ◽  
Nonlinear Free Surface

A fast turnaround and an accurate computational fluid dynamics (CFD) approach for ship total resistance prediction is developed. The approach consists of a nonlinear free surface potential flow solver (PShip code) with a wet-or-dry transom stern model, and a Reynolds-averaged Navier-Stokes (RANS) equation solver that solves viscous free surface flow with a prescribed free surface given from the PShip. The prescribed free surface RANS predicts a viscous correction to the pressure resistance (viscous form) and viscous flow field around the hull. The viscous free surface flow solved this way avoids the time-consuming RANS iterations to resolve the free surface profile. The method, however, requires employing a flow characteristic-based nonreflecting boundary condition at the free surface. The approach can predict the components of ship resistance, the associated wave profile around the hull, and the sinkage and trim of the ship. Validation of the approach is presented with Wigley, Series 60 (CB = 0.6), and NSWCCD Model 5415 hulls. An overall accuracy of ±2% for ship total resistance prediction is achieved. The approach is applied to evaluating the effects of a stern flap on a DD 968 model on ship performance. An empirical viscous form resistance formula is also devised for a quick ship total resistance estimate.

Computer Aided Resistance Prediction Of High Speed Planing Hull Forms

1994 ◽  
pp. 23-43
Author(s):  
Mohd. Ramzan Mainal
Keyword(s):  
High Speed ◽  
Computational Procedure ◽  
Model Testing ◽  
Experimental Results ◽  
Total Resistance ◽  
Computer Prediction ◽  
Computer Aided ◽  
Tremendous Amount ◽  
Resistance Prediction ◽  
Hull Forms

Planing crafts have been the traditional solution to high speed at sea. However, the limitations on high speed planing hull forms in a seaway have led to a tremendous amount of work currently being carried out on hydrofoils, catamarans and hybrid crafts. Despite these facts, the warship, commercial and pleasure markets still show demands for planing crafts and many new designs appear every year. The objective of this paper is to develop a computational procedure for predicting the total resistance of hard chine planing hull forms, prior to model testing. The computer prediction is later validated with existing experimental results.

Effect of Wake on Wave Resistance

1972 ◽  
Vol 16 (02) ◽  
pp. 93-112
Author(s):  
Sander Calisal
Keyword(s):  
Boundary Layer ◽  
Froude Number ◽  
Wave Resistance ◽  
Survey Method ◽  
Viscous Resistance ◽  
Total Resistance ◽  
Ship Model ◽  
A Value ◽  
Design Speed ◽  
Minimum Resistance

Suction is applied to the boundary layer of a ship model designed to be of minimum resistance for a Froude number V/(Lg)1/2= 0.289. The total resistance with suction is measured and the wave resistance is calculated by a wave-survey method. For the design speed the wave resistance is observed to remain almost constant up to a certain suction value and then to increase linearly with suction. The remaining viscous resistance, calculated by subtracting the directly measured wave resistance from the total resistance, decreases by the application of suction to a value lower than the values given by ITTC 57 and Schoenherr curves.

RESISTANCE PREDICTION USING ARTIFICIAL NEURAL NETWORKS FOR PRELIMINARY TRI-SWACH DESIGN

2021 ◽  
Vol 155 (A3) ◽  
Author(s):  
Lt(N) A Carter ◽  
E Muk-Pavic ◽  
T McDonald
Keyword(s):  
Experimental Data ◽  
Design Process ◽  
Training Data ◽  
Resistance Pattern ◽  
Total Resistance ◽  
Form Design ◽  
Hull Form Design ◽  
Resistance Prediction ◽  
Artificial Neural ◽  
Artificial Neural Network Ann

Due to the novel hull form design, at present no standard series or full-scale data is publicly available to predict Tri- SWACH resistance during the preliminary ship design process. This work investigates the viability of using an Artificial Neural Network (ANN) to quickly predict total resistance for preliminary Tri-SWACH design. An ANN was trained using total resistance experimental data obtained from model tests, which varied side hull arrangements. The results highlight strong correlation for model resistance prediction. A Tri-SWACH case study was then developed which had side hull geometric properties different to any previously used to train the ANN. The results, validated against CFD predictions, mimicked the resistance pattern generated by other model experimental data, providing confidence in the ANN’s ability to function as a resistance prediction tool. This work demonstrates the viability of ANN to assess Tri-SWACH resistance as part of a preliminary design process. These results suggest that ANNs can be effective tools for assessing performance given relevant training data.

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 Aspects Influencing the Level Ice Resistance of Ships With Non-Typical Icebreaking Bow Shapes

2021 ◽  
Author(s):  
Daniela Myland ◽  
Quentin Hisette ◽  
Emre Cilkaya ◽  
Yusuf Sefa Özhan
Keyword(s):  
Ice Sheets ◽  
Relevant Information ◽  
Interaction Process ◽  
Total Resistance ◽  
Ship Model ◽  
Load Cells ◽  
Level Ice ◽  
Ice Resistance ◽  
Different Thickness ◽  
Ice Model

Abstract For non-typical icebreaking ships the hull-ice interaction process in level ice comprises a combination of many different phenomena which is difficult to be described by existing straightforward approaches. In order to gain knowledge about the operability of such non-typical hull shapes in level ice, a study has been carried out to identify and evaluate the level ice resistance as well as its distribution along the hull of ships with non-typical icebreaking bow shapes with high stem and/or small waterline angles. For this purpose, one ship model has been manufactured and instrumented with several multi-axis load cells in the bow region of the waterline as well as with one large six-component load scale between the bow and the stern. Performing resistance model tests at several loading conditions in model ice sheets of different thickness and at multiple speed values allows obtaining relevant information to meet the goals of the study. The developed methodology and the analysis of the measured loads have been described in previous publications. As direct continuation, the present paper focuses on investigation of the ice floe characteristics and its linkage to the ice properties. Moreover, analysis results related to the crushing portion of the total resistance in ice, the friction between ice and ship model hull as well as the ship model motions during ice model testing are presented within the paper.

Study of Wave Added Resistance on Wigley Ship

2013 ◽  
Vol 468 ◽  
pp. 105-109
Author(s):  
Tao Sun ◽  
Ming Hui Yuan ◽  
Wei Wang ◽  
Nan Ye
Keyword(s):  
Total Resistance ◽  
Added Resistance ◽  
Ship Model ◽  
Seakeeping Performance ◽  
Head Waves ◽  
Free Model ◽  
Calm Water ◽  
Significant Research ◽  
Energy Consuming ◽  
Hydrodynamic Potential

Global warming is becoming a serious problem nowadays. The emissions of greenhouse gas from vessels draw great attentions. As a significant research part of vessel seakeeping performance, resistance capability exert pretty effect on energy consuming. A Wigley ship model is set as the object to compute constraint and free model in calm water and head waves on resistance and hydrodynamic potential coefficients by STAR-CCM. Differences are discussed between both models. Effects on calculation of hydrostatic resistance ignoring trim and heave are revealed .Wave added resistance of free model is computed and compared at different amplitudes and wavelengths. How trim and heave matter the computed results are discussed. So does how wavelength and amplitudes influence total resistance is considered.

scholarly journals Numerical Investigation of the Shallow Water Effect on the Total Resistance, Vertical Motion and Wave Profile of a Container Ship Model

2021 ◽  
Vol 1182 (1) ◽  
pp. 012005
Author(s):  
A Bekhit ◽  
F Popescu
Keyword(s):  
Viscous Flow ◽  
Shallow Water ◽  
Deep Water ◽  
Flow Simulation ◽  
Vertical Motion ◽  
Wave Profile ◽  
Special Focus ◽  
Container Ship ◽  
Total Resistance ◽  
Ship Model

Abstract A ship sailing in shallow water is affected by the interaction between the moving hull and the seabed in different forms such as: significant increase in total resistance, increase in the sinkage and trim that may result in squatting effect, a change in wave pattern and increased wave amplitude, a change in the propeller wake field and an altered propeller and manoeuvring performance. In order to investigate the influence of shallow water on a container ship that is assumed to be subjected to work in different water depths, the KRISO container ship model is analysed in both deep and shallow water, with a special focus on the change in resistance, vertical motion and wave profile. A viscous flow simulation is performed first to predict the ship performance in deep water and the results are compared with the experimental data that are available in the public domain. Then, the critical shallow water condition is investigated and the obtained results are compared against those formerly obtained in deep water. The numerical simulations are performed using the viscous flow solver ISIS-CFD of the FINETM/Marine software provided by NUMECA. The solver is based on the finite volume method to build the spatial discretization of the transport equation in order to solve the Reynolds-Averaged Navier-Stokes (RANS) equations. Closure to turbulence is achieved using the Menter Shear Stress Transport (K-ω SST) model, while the free-surface is captured through an air-water interface based on the Volume of Fluid (VOF) method. The comparison between the numerically obtained results and the available EFD data showed a satisfactory congruence.

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