CHAPTER ONE
INTRODUCTION
1.1
Background of Research
Naval architecture task is to ensure that, within the bounds of the other design requirement, the hull form design of propulsion and the procedure will be the most efficient in terms of hydrodynamics. The final test of the ship will perform at the required speed with minimum of shaft power, and the problem is to achieve the best combination of low resistance and high efficiency propulsive. In general, this can only be achieved by matching precisely the hull and propeller
In general, the basic contractual obligations are placed on the dock that ship must reach or achieved a certain speed with particular strength in the good weather on trial and for this reason smooth water performance or calm water is very important. 1
Forecast resistance vessel is fundamental topics of interest to naval architects. Hydrodynamic’s been interested in determining the laws of physics related to the ship resistance and speed characteristic. Due to the complicated nature of flow around the ship hull, a satisfactory analytical method relating speed and powering requirement to hull form has not yet been developed. Generally, there are many methods can be used to determine the ship’s resistance. According to Harvald (1983), these methods can be divided into four groups which namely: 1) Model experiments 2) Standard series of experiments 3) Statistical methods 4) Diagrams Model testing is still the most accurate and reliable method but the others may only be used to predict ship resistance between certain limits or only for a ship that comparative data on these groups to forecast. Have similar particulars to such group. For the purpose of this study, only three methods of ship resistance prediction will be discussed in connection with the three groups are shown above. These methods are:
1) Van Oortmersen’s method 2) Holtrop’s and Mennen method 3) Schneekluth’s method
2
1.2
Project Background
The main objective of this project is to study and research on the ship resistance for 28.3m single screw fishing trawler. The ship resistance is normally determined by using model test in a towing tank or circulating water channel. However it can also be predicted by using, empirical formula or statistical data. Prediction in the preliminary design stage is one of the important practice and research in ship design. Several methods can be used in the ship resistance prediction depends on the type of the ship and the limitation of the methods. Consequently using existing method, the resistance of 28.3m fishing trawler will be investigated.
1.3
Objective
i.
To predict the ship resistance of 28.3 trawler by using methodical series
ii.
To calculate manually using the methodical series by means of using computer tools such as Microsoft Excel and later on making source codes using MATLAB or MATHCAD.
iii.
To compare the result of resistance prediction with model test and sea trial result.
iv.
To make limitation as guidelines for methods used in resistance prediction. 3
1.4
Scope of Research
i.
Conduct resistance prediction study in calm water.
ii.
Obtain available experimental data and sea trial results.
iii.
Conduct resistance prediction based on available methods i.e. Holtrop and Mennen.
iv.
Familiarization of programming language and later on generates source codes for resistance prediction calculation.
v.
1.5
Validate prediction result with model experiment.
Problem Statement
In carrying out prediction using methodical series, several issues will be addressed as fallow:i.
How accurate is the present method resistance prediction? It is reliable? 4
ii.
If not? Why it is not reliable at first place? What are the factors contributing to the inaccuracy of these predictions?
iii.
What are the limitations?
iv.
Which method that can be used and reliable in particular for fishing trawler?
1.6
Expected Outcome
i.
Resistance prediction results of 28.3m fishing trawler using the Hullspeed software and manual calculation using Microsoft Excel or programming using MATLAB/MATHCAD.
ii.
Identify methods that can be applied to predict trawler resistance.
5
CHAPTER TWO
LITERATURE REVIEW
2.1
General
6
This chapter will give an overview about the methods that will be used to achieve the objectives of trawler resistance prediction using methodical series.
2.2
Van Oortmersen’s Method[2]
This method is useful for estimating the resistance of small ships such as trawlers and tugs. In this method, the derivation of formula by G. Van Ootmerssen is based on the resistance and propulsion of a ship as a function of the Froude number and Reynolds number. The constraint of this formula is also based on other general parameters for small ships such as trawlers and tugs that are collected from random tank data. The method was developed through a regression analysis of data from 93 models of tugs and trawlers obtained by the Marine Research Institute, Netherlands (MARIN). Besides, few assumptions were made for predicting resistance and powering of small craft such as follows: 1. According to the Figure 2.1 there are positive and negative pressure peak distributions for the hull surface. For the ship hull scope, there are high pressure at the bow and stern, while in the middle it becomes a low pressure.
7
Figure 2.1: Pressure distribution around a ship hull [2]
2. Small ship can be said to have a certain characteristics such as the absence of a parallel middle body, so the regions of low pressure and the wave system of fore and after shoulder coincide and consequently the pressure distribution is illustrated as in figure 2.2.
Figure 2.2: Wave system at fore and aft shoulder [2]
3. The summation of viscous resistance and wave-making resistance representing the components of the total resistance. The range of parameters for the coefficients of the basic expression is as follow:
8
Parameter Length of water line, LWL Volume, ∇ Length/Breadth, L/B Breadth/Draft, B/T Prismatic coefficient, CP Midship coefficient, Cm Longitudinal center of buoyancy, LCB ½ entrance angle, ½ ie Speed/length, V/√L Froude number, Fn
Limitations 8 to 80 m 5 to 3000 m³ 3 to 6.2 1.9 to 4.0 0.50 to 0.73 0.70 to 0.97 -7% L to 2.8% L 10º to 46º 0 to 1.79 0 to 0.50
Table 2.1: Limitations for Van Oortmerssen’s Method
[2]
Van Oortmerssen’s suggested that the final form of the resistance equation is represented by the summation of viscous resistance and wave-making resistance as follow:
9
− ( 1 / 9) m − F2 n − m − F2 n − m − F2 n 1 2 3
( )
−2 RT C e + C e + C e s iFn n+ = −2 + ∆ C4e− m F cn oF −s2n 0.0 ρ7S 52V 2 2( l o R g− n2) ∆
( )
[2.1]
where, 2
1.
10 3 Ci = d i ,0 + d i ,1 LCB + d i , 2 LCB 2 + d i ,3C p + d i , 4 C p + d i ,5 LWL / B + d i , 6 ( LWL / B ) + d i , 7 CWL + d i ,8 ( CWL ) + d i ,9 B / T + d i ,10 ( B / T ) + d i ,11 + C m 2
2
2
[2.2]
2.
m = b1 . − C p
( −b / 2 )
or for small ships this can be presented by: m = 0.14347 − C p
3.
( −2.1976 )
CWL is a parameter for angle of entrance of the load waterline, ie, where
CWL = ie ( LWL / B )
4.
[2.3]
[2.4]
Approximation for wetted surface area is represented by: S = 3.223 V 2 / 33 + 0.5402 LWL V 1 / 3
[2.5]
10
Table 2.2 below shows an allowance for frictional resistance and table 2.3 shows the values of regression coefficient given by Van Oortmerssen’s. Allowance for Roughness of hull Steering resistance Bilge Keel Resistance Air resistance
∆ CF 0.00035 0.00004 0.00004 0.00008 Table 2.2: Allowance for frictional
resistance [2]
di,0 di,1 di,2 di,3 di4 di,5 di,6 di,7 di,8 di,9 di,10 di,11
i 1 79.32134 -0.09287 -0.00209 -246.46896 187.13664 -1.42893 0.11898 0.15727 -0.00064 -2.52862 0.50619 1.62851
2 6714.88397 19.83000 2.66997 -19662.02400 14099.90400 137.33613 -13.36938 -4.49852 0.02100 216.44923 -35.07602 -128.72535
3 -908.44371 2.52704 -0.35794 755.186600 -48.93952 -9.86873 -0.77652 3.79020 -0.01879 -9.24399 1.28571 250.64910
4 3012.14549 2.71437 0.25521 -9198.80840 6886.60416 -159.92694 16.23621 -0.82014 0.00225 236.37970 -44.17820 207.25580
Usually, the Van Oortmerssen’s methods are useful for estimating the resistance of small ships such as trawlers and tugs. In general, Malaysian fishing vessels are short and beamy whilst their draught is relatively low. These kinds of vessel are normally located in shallow river estuaries. These factors will result in a relatively low breadth-draught ratio and block coefficient. 11
2.3
Holtrop’s & Mennen’s Method [2]
This resistance prediction method is one of the techniques widely used in prediction of resistance of displacement and semi-displacement vessels. Like all methods, however, this technique is limited to a suitable range of hull form parameters. This algorithm is designed for predicting the resistance of tankers, general cargo ships, fishing vessels, tugs, container ships and frigates. The algorithms implements are based upon hydrodynamic theory with coefficients obtained from the regression analysis of the results of 334 ship model tests. In their approach to establishing their formulas, Holtrop and Mennen assumed that the non-dimensional coefficient represents the components of resistance for a hull form. It might be represented by appropriate geometrical parameters, thus enabling each component to be expressed as a non-dimensional function of the sealing and the hull form. The range of parameters for which the coefficients of the basic expressions are valid is shown as following:
Ship type
Max
Cp Min
Max
L/B Min
Max
B/T Min Max
no. Tankers, bulk carries 0.24 Trawlers, coasters, tugs 0.38 Containerships, destroyer 0.45
0.73 0.55 0.55
0.85 0.65 0.67
5.1 3.9 6.0
7.1 6.3 9.5
2.4 2.1 3.0
3.2 3.0 4.0
types Cargo liners RORO ships, car ferries
0.56 0.55
0.75 0.67
5.3 5.3
8.0 8.0
2.4 3.2
4.0 4.0
Froude
0.30 0.35
Table 2.4: Limitation for Holtrop and Mennen’s method [2][3]
12
The step by step procedures are shown below to calculate resistance in order to predict the ship power. Calculate: 1.
Frictional Resistance,
RF = (1 / 2 ) ρSV 2 ( C F (1 + k ) + Ca ) [2.6] 2.
Wetted Surface,
( 0.5) 0.4 + 0.45 CB − 430.2 CM20− 8
S = L( 2T + B)CM 0 .
56 2 + 2.3 AB /CB8T ( B0/T) + 0.3 CW 64 P 96 67 [2.7]
3.
Form Factor
(1 + k ) = 0.93 + ( T / L ) 0.22284 ( B / LR ) 0.92497 ( 0.95 − CP ) − 0.52145 (1 − CP ) + 0.0225 LCB 0.6906 [2.8] where,
LR = L(1 − C P ) + 0.06 [2.9] 4.
Correlation Factor, 13
Ca = 0.0006 ( L +100 )
−0.16
− 0.00205
[2.10] 5.
Frictional Resistance Coefficient, CF =
6.
0.075 ( LogRn − 2) 2
[2.11]
Residuary resistance,
R R = Ce ( m1Fn )
−0.9
+ m2 cos ( λFn ) −2
[2.12]
where,
(
(
) )
m1 = 0.0140407 L / T − 1.75254 ∇1 / 3 / L + ( − 4.79323 B / L ) − 8.07981C P 2
+ 13.8673 C P − 6.984388 C P
3
[2.13]
m2 = 1.69385C P e − ( 0.1 / Fn )
[2.14]
λ = 1.446 C P − 0.03 L / B
[2.15]
2
7.
2
Therefore, total resistances are, RT = RF + RR
[2.16]
Generally, Holtrop and Mennen’s method is suitable for a small vessel and this algorithm is designed for predicting the resistance of fishing vessels and tugs. 14
However, with this method, there are still errors exist. Therefore, all the factors below are considered to determine the degree of uncertain parameter: i)
Increasing in Froude number which will create a greater residuary resistance (wave making resistance, eddy resistance, breaking waves and shoulder wave) is a common phenomenon in small ships. As a result, errors in total resistance increase.
ii)
Small vessels are easily influenced by environmental condition such as wind and current during operational.
iii)
For smaller ship, the form size and ship type have a great difference.
This method is only limited to the Froude number below 0.5, (Fn < 0.5) and also valid for TF / LWL > 0.04. There is correlation allowance factor in model ship that will affect some 15% difference in the total resistance and the effective power. This method is also limited to hull form resembling the average ship described by the main dimension and form coefficients used in the method.
2.4
Cedric Ridgely Nevitt’s Method [2]
This method is developed for a model test with trawler hull forms having large volumes for their length. In this method it covers a range of prismatic coefficients from 0.55 to 0.70 and displacement-length ratios from 200 to 500, their residuary resistance contours and wetted surface coefficients have been plotted in 15
order to make resistance estimates possible at speed-length ratios from 0.7 to 1.5. The changing of beam-draft ratio also takes into account the effect on total resistance.
Parameter Length/Breadth, L/B Breadth/Draft , B/T Vulome/length, ∇/ ( 0.01 L ) 3 Prismatic coefficient, CP Block coefficient, CB Speed/length, V/√L Longitudinal center of buoyancy, LCB ½ entrance angle , ½ α˚e
Limitations 3.2 –5 .0 2.0 - 3.5 200 – 500 0.55 - 0.70 0.42 - 0.47 0.7 - 1.5 0.50% - 0.54% aft of FP 7.0˚ - 37.4˚
Table 2.5: Limitations for Cedric Ridgely Nevitt’s method [2]
This method is applicable to fishing vessels, tugs, fireboats, icebreakers, oceanographic ships, yachts and other short and beamy ships falling outside the range of the Taylor Series or Series 60. Procedures of calculating ship resistances using this method are as follows: 16
Calculate: i)
Parameter of V/L for every speed.
ii)
Parameter of ∆/(0.01L) ³ Residuary resistance coefficient CR then can be determined from the graph ∆ / (0.01L) ³ against prismatic CP at every V/L.
iii)
Parameter of B/T ratio The wetted surface coefficient, S /
∇L
value can be determined
from the graph of wetted surface coefficient against prismatic coefficient Cp and calculated B/T ratio iv)
The wetted surface area from the wetted surface coefficient, S/
v)
∇L
Reynolds Number,
Rn =
vi)
ρUL µ
[2.18]
Frictional resistance coefficient, 0.075 ( LogRn − 2) 2
[2.19]
RT = ( C R + C F )( ρ / 2 ) SV 2
[2.20]
CF =
vii)
[2.17]
Total resistance,
After all parameters are calculated, correction needs to be carried out with the total resistance according to the B/T ratio. The correction can be determined from the graph B/T correction factor against V/L. 17
viii)
Calculate the real total resistance coefficient, ' RT = RT x Correction factor
[2.21]
In this method, the resistances are base on the limitation of the parameter.
2.5
DJ. Doust’s Method [2]
DJ. Doust’s Method is used for calculating resistance based on the resistance tests of about 130 trawler models carried out at the National Laboratory in Teddington, England. The results of the tests were transformed into a trawler standard length, between perpendiculars, of 61m (200ft). (Fyson J. 1985) There are six parameters used in the early stage of design. Those parameters are L/B, B/T, CM, CP, LCB and ½ α˚e. Parameter Length/Breadth, L/B Breadth/Draft, B/T Midship coefficient, CM Prismatic coefficient, CP Longitudinal center of buoyancy, LCB ½ entrance angle, ½ α˚e
Limitations 4.4 – 5.8 2.0 – 2.6 0.81 – 0.91 0.6 – 0.7 0% - 6% aft of midship 5˚ - 30˚ 18
Tables 2.6: Limitations for DJ Doust’s Method [2]
This method is relevant to be used in predicting the resistance for fishing vessels. However, correction needs to be taken into consideration for the ships have different length compared to the standard ship length (200ft). Procedures of calculation for DJ Doust’s Method are as follows: i)
Calculate the parameter required to determine factors used to calculate residuary resistance for the ship having standard length, 200 ft. These parameters are L/B, B/T and V/√L.
ii)
Determine three factors used to calculate residuary resistance using graph given. These three factors are F1 = f ( Cp , B / T ) ,
F2 = f ( Cp , LCB )
[2.22]
and
[2.23]
F3 = f ( Cp,1 / 2α , L / B ) '
iii)
[2.24]
Calculate F6 using F6 = 100 a ( C m − 0.875 ). The parameter ‘a’ is a function V/√L and given by Table 6.7
iv)
Calculate residuary resistance, '
C R ( 200 ) = F1 + F2 + F3 + F6 2/3
v)
Calculate,
S = 0.0935S / ∆ 1
vi)
Calculate,
L' =1.05 V /
vii)
Calculate Froude’s skin friction correction,
L
[2.25]
[2.26] [2.27] 19
SFC = SL'
−0.175
(0.0196 + 0.29 L / 10 '
4
2
3
− 2.77 L' / 10 6 + 1.22 L' / 10 8
)
[2.28] viii)
Calculate,
δ 1 = (152.5 x SFC ) / ∆ ( 200 ) ix)
1/ 3
Calculate residuary resistance for new ship, C R ( new ) = C R ( 200 ) + δ1
x)
[2.29]
[2.30]
Calculate total resistance,
RT =
V/√L 0.8 0.9 1.0 1.1
C R ( new ) ∆V 2 L
[2.31]
A -0.045 -0.053 -0.031 -0.035 Tables 2.7: Values parameter ‘a ’[2]
20
2.6
Schneekluth’s Method (Taylor – Gertler and Harvald – Guldhammer)
This method consists of residuary resistance and Frictional resistance in order to obtain the total resistance of a ship. RT = RF + RR
[2.32]
2.6.1 Residuary Resistance The residuary resistance of a new design is not quite so easy to calculate as its frictional resistance. The coefficient of residuary resistance (CR) of a merchant ship having the optimum position of the LCB can be approximated using the following formula developed by Schneekluth. The formula tends to smooth out the effect of the humps and hollows of the resistance curves. It is based on the published residuary resistance curves of Taylor – Gertler and Harvald - Guldhammer. 103 CR = (10Fn - 0.8)4 (10CP - 3.3)2 (103Cv + 4)0.0012 + (103 Cv 0.05) + 0.2 + (B/T - 2.5)0.17
[2.33]
where CR is the coefficient of residuary resistance 21
Cv = Volume/L3
[2.34]
and the other terms have their usual meanings. The residuary resistance is then given by RR = 0.5ρSv2CR
[2.35]
The limits of validity of the formula are: 0.17 < Fn < 0.30 2.0 < 103 Cv < 11.0 0.50 < CP < 0.80 CB ≤ CB (Ayre) + 0.06 (CB (Ayre) = 1.08 - 1.68Fn ) 5.0 < L/B < 10.0 2.0 < B/T < 4.5 The formula should not be used outside the specified limits.
2.6.2 Frictional Resistance The International Towing Tank Conference (ITTC) is a body which coordinates research into ship hydrodynamics. By studying a wide range of experiments in which the resistance of ships, ship models, planks and other objects was measured and by looking at the underlying scientific principles a consensus was reached as to the most reliable way of predicting the variation of frictional resistance of a smooth surface with Length and Speed. This is normally referred to as the 1957 ITTC Line. The modern method for calculating the frictional resistance of a ship is to use the 1957 ITTC Line with a roughness allowance (typically taken as 0.0004) added to take account of the distinctly unsmooth surface of a real ship: Cf = 0.0004 + 0.075 / (log10Rn - 2 )2
[2.36] 22
where Cf is the coefficient of frictional resistance 0.0004 is a roughness allowance and Rn is Reynolds Number given by Rn = vL / ν
[2.37]
where v is the ship's speed in m/s ν is the kinematic viscosity which takes the following typical values: In Fresh Water at 15 deg C 1.139×10-6 m2/s In Salt Water at 15 deg C 1.188×10-6 m2/s
The frictional resistance is then given by RF = 0.5ρSv2Cf`
[2.38]
where ρ is the density of water in kg/m3 S is the wetted surface area in m2 and may be given by S = 1.7LT + LBCB (The Denny - Mumford formula)
[2.39]
L is the ship's length in m
23
CHAPTER THREE
RESEARCH METHODOLOGY
24
3.1
General
This chapter puts emphasis on the using of methodical series to calculate manually by means of using computer tools such as Microsoft Excel and later on making source codes using MATHCAD or MATLAB to predict the ship resistance and compare the results with existing program such as Hullspeed.
3.2
Computer Programs
3.2.1 Hullspeed
Only one computer software is chosen to predict the ship resistance which is Hullspeed from FormSys. The selected computer program is to determine the ship’s resistance which is more accurate than calculating it manually using the selected methods. The data that been produce by the programs will be used as guidelines and limitations to help calculating the ship’s resistance by using methodical series.
25
Hullspeed[6] provides a means of predicting the resistance of a ship hull. Maxsurf designs may be read in and automatically measured to obtain the required parameters, or the parameters may be typed by hand without the need for an existing Maxsurf design file. If the overall efficiency of the propulsion installation is known, or may be estimated, the power requirements of the design may be predicted. Given the data required for the resistance prediction algorithms selected for analysis, Hullspeed will calculate the hull resistance at a range of speeds and will give results in graphical and tabular formats. These results may be copied to a spreadsheet or word processor for further analysis and/or formatting. Hullspeed supports resistance prediction calculations for a wide range of monohulls and multihull. Many different approaches exist to predict the resistance of a vessel. Hullspeed implements several different resistance prediction algorithms, each applicable to various families of hull shapes. For example, some of the algorithms are useful for estimating the resistance of planning hulls, while others are useful for estimating the resistance of sailing boat hulls.
Besides resistance prediction calculations, Hullspeed can also be used to calculate the wave pattern generated by the vessel for a given velocity. It should be emphasised that resistance prediction is not an exact science and that the algorithms implemented in this program, while they are useful for estimating the resistance of a hull, may not provide exact results. Hullspeed is essentially a resistance prediction program. A number of regression-based methods and one analytical method can be used to predict the resistance of the hull form. It is normal naval architecture practice to break down the resistance into components which scale according to different laws. Hullspeed can calculate the resistance components in coefficient form. However, since different methods use different formulations, not all the resistance components may be available.
26
3.2.2 MathCAD
MathCAD is computer software primarily intended for the verification, validation, documentation and re-use of engineering calculations. First introduced in 1986 on DOS, it was the first to introduce live editing typeset mathematical notation combined with its automatic computation. It was also the first to automatically compute and check consistency of engineering units such as the International System of Units (SI). MathCAD today includes some of the capabilities of a computer algebra system but remains oriented towards ease of use and numerical engineering applications.
27
MathCAD was conceived and originally written by Allen Razdow (of MIT), co-founder of Mathsoft which is now part of Parametric Technology Corporation. MathCAD is oriented around a worksheet, in which equations and expression are displayed graphically, as opposed to a plain text, an approach alter adopted by other systems such as Mathematica. Among the capabilities of MathCAD are: • Solving differential equations, with several possible numerical methods • Graphing functions in two or three dimensions • Symbolic calculations including solving systems of equations • Finding roots of polynomials and functions •
Statistical functions and probability distributions
• Calculations in which units are bound to quantities Although this program is mostly oriented to non-programming users, it is also used in more complex projects to visualize results of mathematical modelling using distributed computing and traditional programming languages.
3.2.3 MATLAB
MATLAB (matrix laboratory) is a numerical computing environment and fourth-generation programming language. Developed by Mathworks, MATLAB allows matrix manipulations, plotting of functions and data, implementation of algorithms, creation of user interfaces, and interfacing with programs written in other languages, including C, C++ and FORTRAN. 28
Although MATLAB is intended primarily for numerical computing, an optional toolbox uses MuPAD symbolic engine, allowing access to symbolic computing capabilities. An additional package, Simulink, adds graphical multidomain simulation and Model-Based Design for dynamic and embedded systems. In 2004, MATLAB had around one million users across industry and academia. MATLAB users come from various backgrounds of engineering, science and economics. Among these users are academic and research institutions such as Georgia Tech, Massachusetts Institute of Technology, NASA, Canterbury University and RWTH Aachen University as well as industrial enterprises such as ABB Group, Boeing, Caterpillar Inc., Halliburton, Motorola, Philips, Toyota and UniCredit Bank. In addition to the usage of MATLAB B being integrated into teaching of Engineering and Linear Algebra courses, as part as their Continuing Studies programs, many Community Colleges and Universities are creating stand-alone MATLAB courses focused on just teaching the MATLAB user interface and script writing. These courses are especially tailored for returning students going back for a higher-level degree and for students who graduated many years ago before MATLAB was integrated into the educational system.
3.3
Methodical Series
There are 3 main methods that will be used when calculating the ship’s resistance which are Holtrop and Mennen’ method, Van Oortmersen’s method and Schneekluth’s method. Using these methods and calculating the resistance using their formulas in Microsoft Excel, the ship’s resistance prediction will be obtained. Even 29
though the answer have been obtained, each of the methods came with its own limitations that need to be consider before the actual results can be compare with the results that been obtained using Hullspeed.
3.4
Collect Experiment Data
There was a model test have been done in UTM which the result can be used to compare to the results that obtained by computer programs and methodical series. It also can be as guidelines so that the results still have the same value but maybe have a little margin.
3.5
Research Flow Chart
The flow chart mention in the Appendix A.
30
3.6
Research Master Schedule
The Master schedule mention in Appendix B.
CHAPTER FOUR
31
DEVELOPMENT OF COMPUTER PROGRAMMING USING MATLAB AND MATHCAD
4.1
General
This chapter will explain the software that being used to program the resistance calculation using the chosen methods. The guidelines that had been set up using Microsoft Excel and result from Hullspeed will be compared with the program that will be set.
4.2
MATLAB
MATLAB® is a high-level technical computing language and interactive environment for algorithm development, data visualization, data analysis, and numeric computation. Using the MATLAB product, it can solve technical 32
computing problems faster than with traditional programming languages, such as C, C++, and FORTRAN. MATLAB can be used in a wide range of applications, including signal and image processing, communications, control design, test and measurement, financial modelling and analysis, and computational biology. Add-on toolboxes (collections of special-purpose MATLAB functions, available separately) extend the MATLAB environment to solve particular classes of problems in these application areas. MATLAB provides a number of features for documenting and sharing users work. You can integrate your MATLAB code with other languages and applications, and distribute your MATLAB algorithms and applications. Below are the key features: • High-level language for technical computing • Development environment for managing code, files, and data • Interactive tools for iterative exploration, design, and problem solving • Mathematical functions for linear algebra, statistics, Fourier analysis, filtering, optimization, and numerical integration • 2-D and 3-D graphics functions for visualizing data • Tools for building custom graphical user interfaces •
Functions for integrating MATLAB based algorithms with external applications and languages, such as C, C++, Fortran, Java, COM, and Microsoft Excel
4.3
Source Coding Process Flow
33
Basically, the process of source coding of MATLAB is similar with other source coding programs such as FORTRAN. Users just need to key in the main particular or formula that will be used to make the program running as in this case is to calculate the ship resistance. First, user need to open the program and create a filename based on the program that will be set in order for the programmer or other user to use the program. This process is to distinguish the program that been created so that it will not be mixed with other similar program but different method or etc. Next, from the formula that been used before when calculating manually using Microsoft Excel, programmer have to determine the main particular that will be change when to calculate other vessel’s resistance. Then, the velocity of the ship must be determined so it will automatically calculate the Froude number, for looping process and for other variables in the formula used. Further more write the formula that being used to calculate the resistance one by one and determine what the formula is for so that it will not confused other user what is that formula for. Make sure that the formula is written according to its arrangement to prevent from miscalculation or mixed up. Write until the last variables of the formula and then proceed with running the program. See whether the program have problem or not. If there wasn’t any problem occur, than the prediction of the total resistance of the ship can be gain from the program and compared with the formula manually calculated and with other familiar program been used to calculate ship resistance. If there were problem, the software will identify which line that is incorrect or cannot be read by the software. So the problem will be identify by try and error or search the manual what the causes of the problem and try to rewrite the line and rerun the program again. If still have problem, identify and rewrite the incorrect line until the program can produce the appropriate results. 4.4
MathCAD
34
Engineers, scientists and other technical professionals across the world use MathCAD to perform, document and share calculation and design work. The unique MathCAD visual format and easy-to-use scratchpad interface integrate standard mathematical notation, text and graphs in a single worksheet, making MathCAD ideal for knowledge capture, calculation reuse and collaboration. MathCAD drives innovation and offers significant personal and process productivity advantages for product development, engineering design projects and hundreds of other applications where calculations are key. Unlike proprietary calculating tools and spreadsheets, MathCAD lets you document, format and present your work while applying comprehensive mathematical functionality and dynamic, unit-aware calculations. MathCAD lets you work with updatable, interactive designs, allowing you to capture the critical methods and values behind each of your projects. Benefits: • Easy to learn and use - no special programming skills required • Increases productivity, saving time and reducing errors • Improves verification and validation of critical calculations • Promotes calculation best practices and reuse of calculation content • Complete documentation of calculations supports standards compliance
4.5
Source Coding Process Flow 35
Basically, the process of source coding of MathCAD is similar with other source coding programs such as FORTRAN. Users just need to key in the main particular or formula that will be used to make the program running as in this case is to calculate the ship resistance. First, user need to open the program and create a filename based on the program that will be set in order for the programmer or other user to use the program. This process is to distinguish the program that been created so that it will not be mixed with other similar program but different method or etc. Next, from the formula that been used before when calculating manually using Microsoft Excel, programmer have to determine the main particular that will be change when to calculate other vessel’s resistance. Then, the velocity of the ship must be determined so it will automatically calculate the Froude number, for looping process and for other variables in the formula used. Further more write the formula that being used to calculate the resistance one by one and determine what the formula is for so that it will not confused other user what is that formula for. Make sure that the formula is written according to its arrangement to prevent from miscalculation or mixed up. Write until the last variables of the formula and then proceed with running the program. See whether the program have problem or not. If there wasn’t any problem occur, than the prediction of the total resistance of the ship can be gain from the program and compared with the formula manually calculated and with other familiar program been used to calculate ship resistance. If there were problem, the software will identify which line that is incorrect or cannot be read by the software. So the problem will be identify by try and error or search the manual what the causes of the problem and try to rewrite the line and re-run the program again. If still have problem, identify and rewrite the incorrect line until the program can produce the appropriate results.
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CHAPTER FIVE
EXTRAPOLATION FROM UTM MODEL TEST
5.1
General
This chapter explain the method used to extrapolate the data taken from model test done in UTM towing tank (Muslim, 2010) and convert the data to RTs and compared it with the result gain from calculations.
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5.2
Introduction
Extrapolation methods are methods that are being used to convert the results or data obtained from model tests to full-scale condition. In model powering test, the results obtained are meant for the specific size of the model and does not present the actual powering requirement for the full-scale ship. Thus there is a need to extrapolate the result obtained from model test to full-scale ship. Model test is an experiment conducted on a small-scale ratio model. Model testing is meant to estimate the hydrodynamic quantities such as resistance powering or sea keeping requirement of full-scale ship through the technique of extrapolation of the data obtained from model test.
5.3
Experiment Data The data that been collected from UTM Marine Technology Laboratory have
to be extrapolated to get the correct result that needs to calculate and predict the resistance of the trawler. Rtm
Ctm
Vs (m/s)
7.10E+00 1.05E+01 1.35E+01 1.81E+01 2.54E+01 3.80E+01
0.0069505 0.0083360 0.0088552 0.0099539 0.0119154 0.0153684
4.6296 5.1440 5.6584 6.1728 6.6872 7.2016
Vs (knots) 9 10 11 12 13 14
Fn
Rnm
0.2779 0.3087 0.3396 0.3705 0.4013 0.4322
2767824.561 3074210.526 3380596.491 3689052.632 3995438.596 4303894.737
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Rns 110098890.8 122332100.8 134565310.9 146798521 159031731.1 171264941.2
Crs 0.0006145 3 0.0021281 7 0.0027599 6 0.0039594 0 0.0060108 8 0.0095459 2
Cfm 0.00380 0.00372 0.00366 0.00360 0.00354 0.00349
Ca 0.0004 1 0.0004 1 0.0004 1 0.0004 1 0.0004 1 0.0004 1
Cfs 0.00205 0.00202 0.00200 0.00197 0.00195 0.00193
Caa 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2
Fn^4 0.0059616 0.0090729 0.0132673 0.0188135 0.0258861 0.0348543
Cts 0.004649 6 0.006111 9 0.006698 3 0.007857 1 0.009871 8 0.013373 3
Fn4/Cfm Ctm/Cfm 1.568507 1.82868 2.436333 2.23848 3.628481 2.42182 5.231827 2.76807 7.308310 3.36402 9.978857 4.40002
(1+k) 1.667 1.667 1.667 1.667 1.667 1.667
Rts(N) 8406.15496 13641.97308 18090.43903 25253.52860 37237.62409 58505.33735
Table 5.3. Extrapolation Data of Fishing Trawler
5.4
Model Test Analysis
From the result that been extrapolated from the model test that being done in UTM towing tank and compared with the resistance result obtained from Hullspeed, researcher can see that the total resistance of the model is almost similar pattern of the graph which is the model test is the most accurate but it has to be done in many 39
runs in order to get most accurate data from the test. But by using this single run test, we can see that the resistance result is almost the similar to each other but the small differences may be cause of the limitations of each formula and the machine flaws.
Figure 5.1 Comparison for Trawler Resistance
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Figure 5.2 Comparison of Hullspeed and Model Test
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CHAPTER SIX
RESULT COMPARISON AND ANALYSIS
6.1
General
In this chapter will explain the concept of three methods that use in this project. As the objective of the project is to prove the empirical formulae include 3 methods (Holtrop and Mannen, Van Oortmesen, Schneekluth’s) are relevant and validate the result with model test and programmed software by comparing the result. However, due to parameter limitation we have to come out with 3 difference type of vessel (fishing trawler, Frigate. Tanker), those have different length, beam, draft and reliable result according to limitation.
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6.2
Result Comparison
By creating source code programming software made easier the work using MATLAB base on the empirical formula come up with result that be compared with Hullspeed And Model Test.
6.2.1 Trawler Resistance Prediction
To predict the trawler resistance using vessel main input parameter are enclosed to the MATLAB programming with 3 methods to achieve result. However result from MATLAB are not the end result, it must be compared with Hullspeed result and Modal Test. Below is the graph shown the result from empirical formula, software and model test;
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Figure 6.2.1: Resistance Prediction for 28.3m Trawler
The result are been plot to the graph above and shown the result from empirical formula, software and model test. From the result attained that the values and pattern of the graph almost identical only at the coefficient resistance (CT) around 5.00E-03 to 1.50E-02. When regardless the limitation ratio, the value start not coherent and reliable. Limitations of the 3 methods need to be considered, and not all value is consistent can be used. It is because the difference of usage of formula between MATLAB coding and Hullspeed creates the large gaps with the range value. In this case the usage of the formula which is possibly slightly difference from reciprocally. Bear in mind the limitation should not be neglected.
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6.2.2 Frigate Resistance Prediction The result produce from 2 source coding MATLAB and MathCAD, illustrated the similar result with programmed software Hullspeed to be compare. But nevertheless the difference occurs effected in value and graph pattern.
Figure 6.2.2. Resistance Prediction for 80m Frigate
The deviation between the MATLAB source coding and Hullspeed result almost the similar, but the Frigate data is a remade lines plan to ensure and validate the empirical method with the program software. So the result between 2 data Holtrop Mannen almost identical; however without model test for frigate cannot assume the data as final result. It just imaginary linesplan as a guideline to ensure the empirical formula and the software data are relevant. Normally, this method is 45
suitable to be used to calculate the resistance for small vessel within 40m to 120m length range.
6.2.3 Resistance Prediction for Tanker The method and formula to conduct prediction are the same as the proven software used. But the data result slightly gave different on value went in goes bigger froud number and from formulae that been used nowadays. For this type vessel besides Holtrop and Mannen Formulae, Schneekluth( Taylor – Gertler and Harvald – Guldhammer) a modified method also suitable to use. Below shown the graph of tanker obtained from using Schneekluth formula compared with Holtrop and Mennen from Hullspeed.
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Figure 6.2.3. Resistance Prediction for 100m Tanker
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6.3
Analysis of Selected Methods
There is 5 different method that been found only 3 methods are reliable which is Van Oortmersen, (Holtrop and Mannen) and Schneekluth( Taylor – Gertler and Harvald – Guldhammer). From the chosen methods, there are parameter on limitation need to be consider before resistance prediction can start. It is because ensure the parameter of the vessel are not out of the range or less than range that will affected accuracy of values and results. From the reseach noticed that for a small vessel such as fishing trawler are suitable to calculate resistance with Holtrop and Mannen and Van Oortmesen method. In this case for 28.3m fishing trawler are not reliable to use calculate the resistance using Holtrop and Mannen method because the vessel parameter are less the range within the limitation. To estimating resistance for the trawler, the Van Oortmesen method is useful for predict the resistance. Due to parameter limitations, reseacher need to expend the reseach on the others 2 methods and not only focusing on one method that only can calculate for the small vessel. By adding with 2 differrent type of vessel the research will expand. A method has been determined to be useful to calculate small vessel resistance but to calculate medium and large vessel, it is more appropriate to use Schneekluth’s and Holtrop and Mennen’s method respectively
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Below are the graphs being compared with all the methods being used to calculate the resistance for frigate and tanker plus with model test result:-
Figure 6.3.3. Resistance Prediction for 80m Frigate
The differences of percentage and the accuracy of the method can be shown through the bar graph as below.between 2 model data, the method schneekluth is the most realiable to be used in this method. however, when using on small vessel and not following the limitation test, they will be some difficulties on facing with total resisnatce of the modal test, as when using appropriate method and limitation, we will have a result that is accurate and precise. 49
Figure 6.3.4. Percentage Differences of Fishing Trawler
Figure 6.3.5. Percentage Differences of 100mTanker
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CHAPTER 7
CONCLUSION AND RECOMMENDATION
7.1
Conclusion
Only one method that can be used to calculate the fishing trawler’s resistance and that is Van Oortmersen’s method. The other two are not reliable enough due to their formula limitations but it can be used to calculate the resistance of other type of vessels such as frigate and tanker. This program can be used widely for student to calculate and predict their ship’s resistance and help them to calculate the powering requirement to propel their vessel. Even though there is many reliable software or programs that exist nowadays to calculate and predict the vessel’s resistance and powering, this program is also 51
reliable and can be used like other existing and well-known program such as Hullspeed. This program can calculate the resistance without having the user have to draw or design the shape of the vessel. This program just need main particulars to calculate the resistance and can give the result that almost similar to well-known software. Even the user is using the well-known program and can get the right values and results, they still have to recalculate and get the new values that change because the design process is in spiral and kept repeating/changes again and again until get the final and satisfied results that meet the owner requirement.
7.2
Recommendation
For future recommendation, to be a naval architecture, they should learn and know the basic empirical formula to calculate the resistance and other properties so that they would understand what they are doing. This is because to train them not to depend on the programming software that only needs clicking to get the results. This will train them to be more alert and mature to handle and solve any problem occur in the future.
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References
1. SV. AA. Harvald, Resistance and Propulsion of Ships 2. Alizam, UTM. 3. Dr. Mohamad Pauzi Abd. Ghani, Ship Resistance, UTM. 4. Rawson and Tupper, Basic Ship Theory Vol.2 5. J. D. van Manen P. van Oossanen, Principle of Naval Architecture Vol.2 6. Hullspeed Manual. 7. Navcad, HydroComp Inc. 8. Mr D.L. Smith. Marine design, Universities of Glassgow& Strathclyde
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APPENDIX AAPPENDIX A Flow Chart
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START
LITEREATURE REVIEW
METHODOLOGY
SELFPROGRAMMING
VAN OORTME RSEN
COLLECT EXPERIMENT DATA
SOFTWARE
HOLTROP AND MENNEN
UTM MODEL TEST DATA NAVCAD 2007
HULLSPEED ®
SCHNEEK LUTH
Resistance prediction for single screw ships ITTC 1978
ANALYSIS
LIMITATION AND GUIDELINES
COMPARISON STUDY
REPORT
APPENDIX B Master Schedule
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APPENDIX C 57
3D and 2D Modelling In this appendix to shown the model of the vessel in 2D and 3D view for references.
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60
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APPENDIX D Programming of Rapid Prediction Resistance Flow Chart In this appendix, the flow chart of the ‘Rapid Prediction Resistance’ writen in MATLAB R2010a. There is 3 method to be program in this programming. HOLTROP AND MANNEN PROGRAMMING FLOW CHART
OPEN
CREATE FILE NAME LOOPING FOR VARIOUS SPEED
CG
Velocity =1:1:25
C15
CODE THE MAIN SHIP PARTICULAR LAMDA
PROPERTIES OF WATER
C4
CRITERIA/ LIMITATION OF ADDITIONAL COEFFICIENT
RTOTAL =(RF*kf ac)+RW+RtR+R B+RA
C12
RESULT
C16
END FORM FACTOR
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SCHNEEKLUTH PROGRAMMING FLOW CHART
OPEN
CREATE FILENAME
LOOPING FOR VARIABLE SPEED
for
`
Velocity =1:1:25
CODE THE MAIN SHIP PARTICULAR mu=1.188E-06;
VOLUME=L*B*T*CB
FROUDE NUMBER(Fn)
Cvol = Volume / (L^3);% must be between 0.002 and 0.011
Rn=((V*L)/ mu);
Cf = 0.0004+(0.0075/ ((log10(Rn))2)^2);
Rf=0.5*rho*S*(V ^2)*Cf;
end
Cr = ((((( 10*Fn)-0.8)^4)*(((10*Cp)3.3)^2)*(((10^3)*Cvol)+4)*0.0012)+... (((10^3)*Cvol)*0.05)+0.2+(((B/ T)-2.5)*0.17))/1000;
Rt=Rf+Rr
RESULT
Rr=0.5*rho*S*(V ^2)*Cr;
ANALYSIS AND RECOMMENDATION
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VAN OORTMESSEN PROGRAMMING FLOW CHART OPEN
LOOPING FOR VARIABLE SPEED
CREATE FILENAME
For
Velocity =1:1:25
CODING SHIP MAIN PARTICULA R
C1
ANGLE OF ENTERANC E
C2
FROUDE NUMBER (Fn)
C3
mu = %kinematic viscosity of sea water in m^2/s
Rn=((Velocity*L) /mu);
C4
RTper_displace ment=RRper_di splacement+RF per_displaceme nt;
RT = RTper_displace ment
m=0.14347*(Cp ^-2.1976); end RESULT
CWL=ie*(3.142/180)*(L/ B);
CWL=ie*(3.1 42/180)*(L/ B);
RRper_displacement=((C1*exp((m*(Fn^2))/9))+(C2*exp(-m*(Fn^2)))+... (C3*exp(m*(Fn^2)))*(sin((Fn^-2)*(3.142/ 180)))+... (C4*exp(m*(Fn^2)))*(cos((Fn^-2)*(3.142/ 180))));
ANALYSIS AND RECOMMENDATION
RFper_displacement=(0.075*rho*S* (Velocity^2))/(2*(((log10(Rn))2)^2)*displacement);
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APPENDIX E SOURCE CODING AND INPUT DATA In this appendix. The show the conducting the input data for the program ‘Rapid Prediction Resistance’ writen in MATLAB R2010a ,that being develop in this project. VAN OORTMESSEN INPUT
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SCHEEKLUTH INPUT
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HOLTROP AND MANNEN INPUT
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70
71
72
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