Flow Around Ship Like Two Object

1
YILDIZ TECHNICAL UNIVERSITY
NAVAL ARCHITECTURE AND MARITIME FACULTY
DEPARTMENT OF NAVAL ARCHITECTURE AND MARINE
ENGINEERING
FLOW AROUND SHIP LIKE TWO OBJECT
110A2050
UĞUR CAN
110A2003
İSMAİL HAKKI TOPAL
BSc. DESIGN PROJECT
ADVISER
ASSOC.PROF.DR. SEYFETTİN BAYRAKTAR

2
FOREWORD
We would like to express my sincere thanks to Assoc.Prof.Dr. Seyfettin BAYRAKTAR who
enables me to work on this topic. His guidance and motivation leads us to learn the present
topic and finish the project on time.
June 2015
Uğur CAN
İsmail Hakkı TOPAL

3
CONTENTS
page
FOREWORD……………………………….………………………………………………………………………………………………2
CONTENTS…………………………….…………………………………………………………………………………………………..3
ABBREVIATION LIS.………….………………………………………………………………..……………………………………….6
FIGURE LIST…………………….…………………………………………………………………………………………………………7
TABLE LIST…….……………….……………………………………………………….…………………….…….…………………….9
ABSTRACT………………………….……………………………………………………………………………………………………10
CHAPTER 1. INTRODUCTION………………………………………………………………..………………………………….11
1.1 A Ship……………………………….…………………………………………………..………………………………………11
1.2 A Cargo Ship……………………………….………………………………………………………………………………..11
1.3 Reason of Building Ships……………………………….………………………….…………………………………..12
CHAPTER 2. DESIGN……………………………….……………………………………………………..…………………………13
2.1 Design……………………………….………………………………………………………………..…………………………13
2.2 Design Spiral……………………………….…………………………………………………………………………………14
CHAPTER 3. DESING METHODS……………………………….……………….………………………………………………15
3.1 General……………………………….…………………………………………………………………………………………15
3.2 3-D Computer Modelling……………………………….………………………………………………………………16
CHAPTER 4. MAIN DIMENSIONS……………………………….……………..………………………………………………17
4.1 Design Requirements……………………………….……………………………………………………………………17
4.2 Determined Main Dimensions……………………………….………………………………………………………17
4.3 Regression Analysis……………………………….………………………………………………………………………17
4.4 Tables of Regression Analysis…………………………………………………..……………………………………19
CHAPTER 5. DESIGN OF A CARGO SHIP………………………………………………….…………………………………21
5.1 Main Dimensions……………………………….…………………………………………………….……………………20
5.2 Offset Table……………………………….……………………….…………………………………………………………20

4
CONTENTS
page
5.3 Drawings First Cargo Ship……………………………….………………………………………..……………………22
5.4 Drawings Second Cargo Ship……………………………….…………………………………………………………25
CHAPTER 6. ANALYSIS……………………………….……………………………………………………………..………………27
6.1 Hydrostatic values about first ship……………………………….……………….………………………………27
6.2 Hydrostatic values of second ship…………………………………………….……………………………………28
6.3 Resistance values that affect to first ship……………………………….…..…………………………………29
CHAPTER 7. COMSOL.……………………………….……………………………………………………………..………………33
7.1 Introduction……………………………….………………………….……………………………………………………..33
7.2 CFD Module……………………………….………………………….……………………………………..……………….33
7.3 Physics Interfaces Appropriate for Any Type of Flow……………………………………………………34
7.3.1 Single-Phase Flow……………………………….………………………….………………………….………..34
7.3.2 Nonisothermal Flow……………………………….………………………….………………………………..34
7.3.3 Compressible Flow……………………………….………………………….………………………………….34
7.3.4 Two-Phase Flow……………………………….………………………….…………………………………….35
7.3.5 Porous Media Flow……………………………….………………………….…….……………………………35
7.3.6 Rotating Machinery……………………………….………………………….…………………………………35
7.3.7 Thin-Film Flow……………………………….………………………….…………………….…………………..37
7.3.8 Non-Newtonian Flow……………………………….………………………….………………………………37
7.3.9 Flow Through Thin Screens……………………………….………………………………..…….…………38
7.3.10 Fluid Flow and Heat Transfer……………………………….…………………………………….………38
7.3.11 Reacting Flow……………………………….………………………….………………………………………..38
7.4 Simulation Software for All Fluid Flow Applications……………………………………………………….38
7.5 Unified Platform for Multiphysics and Multidisciplinary Simulations……………………..………39

5
CONTENTS
page
7.6 Approaching Your Final CFD Solution in Stesps………………………………………………………………40
7.7 Tools for Providing Flexibility within Meshing and Robust Solving…………………….……………40
7.8 Extract Accurate and Descriptive Data from CFD Simulations…………………………………….….41
7.9 COMSOL Desktop………………………………………………………………………………………………...……….42
7.10 Creating a New Model………………………………………………………………………….……………………..44
7.10.1 Creating a Model Guıded By The Model Wizard………………………………………………….……44
CONCLUSION……………………………………………………………………………………………………………………………54
REFERENCES……………………………………………………………….……………………………………………………………54
CURRICULUM VITAE……………………………………………..………….………………………………………………………55

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ABBREVIATIONS LIST
3-D: 3-Dimensional
DWT: Deadweight Tonnage
Vs: Velocity of ship
L: Lenght
B: Beam
D: Depth
T: Draught
A.P: Aft Perpendecular
F.P: Fore Perpendecular
WL: Water Line L Length
Cp: Prismatic Coefficent
Cb Block Coefficent
Cm Maximmum Section Area Coefficent
Cwp Waterplane Area Coefficent
LCB Lenght of Buoyancy Centre
LCF Lenght of Area Centre
Fwd Forward
KB Height of Buoyancy Centre
KG Height of Gravity
BMt Metacentric Radius
GMt Metacentric Height
KMt Transverse Metacentre
TPc Immersion
MTc Force of 1 cm Moment
RM Force of 1 Degree Trim

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FIGURE LIST
Page
Figure 1.1 Cargo ship………………………………………………………………………………….………………………11
Figure 2.1 Design spiral…………………………………………………………………………………………….….……14
Figure 3.1 Early project phase virtual model of a dry cargo ship……………………………………..…..16
Figure 5.1 Sections of the ship………………………………………………………………………………………..…..22
Figure 5.2 Profile view of the ship…………………………………………………………………………………….…22
Figure 5.3 Water lines of the ship………………………………………………………………………………………..23
Figure 5.4 Perspective view of the ship in Maxsurf……………………………………………………………..23
Figure 5.5 Perspective view of the ship in Rhino………………………………………………………..………..24
Figure 5.6 Generally drawings in Rhino…………………………………………………………………….…………24
Figure 5.7 Section view of the ship…………………………………………………………………………..………….25
Figure 5.8 Profile view of the ship………………………………………………………………………………….…..25
Figure 5.9 Drawing water lines of the ship………………………………………………………………..………..26
Figure 5.10 Perspective view of the ship………………………………………………………………….………….26
Figure 6.1 Hydrostatic values of first ship…………………………………………………………….……………..27
Figure 6.2 Hydrostatic values of second ship…………………………………………………………..………….28
Figure 6.3 Effective Power- Speed Graphic…………………………………………………………..……………..29
Figure 6.4 Total Resistance Coefficient-Speed Graphic…………………………………………….………….29
Figure 6.5 Residuary Resistance Coefficient-Speed Graphic…………………………………………………30
Figure 6.7 Wave Resistance Coefficient-Speed Graphic………………………………………..…………….30
Figure 6.8 Friction Resistance Coefficient-Speed Graphic…………………………………………………….31
Figure 6.9 Viscous Resistance Coefficient-Speed Graphic…………………………………………………….31
Figure 6.9 Correlation Coefficient-Speed Graphic…………………………………………………………..……32
Figure 7.1 Comparison of the flow field in a 2D approximation with the 3D model of a
baffled, turbulent reactor……………………………………………………………………………………………………33
Figure 7.2 Flow field in a stirred, baffled mixer using the Rotating Machinery interface…..…36

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FIGURE LIST
Page
Figure 8.1 First model like a pontoon which has ship’s dimensions………………………………………….46
Figure 8.2 First towing tank and pontoon…………………………………………………………………………………46
Figure 8.1 First model like a pontoon which has ship’s dimensions………………………………………….47
Figure 8.2 First towing tank and pontoon…………………………………………………………………………………47
Figure 8.3 Normal size meshing mdel and towing tank…………………………………………………………….48
Figure 8.4 Velocity analysis of model……………………………………………………………………………………….49
Figure 8.5 Pressure analysis of model………………………………………………………………………………………49
Figure 8.6 Sylindirical Model…………………………………………………………………………………………………….51
Figure 8.7 Second towing tank and sylindirical model………………………………………………………………51
Figure 8.8 Coarse size meshing model and towing tank……………………………………………………………52
Figure 8.9 Velocity analysis of second model……………………………………………………………………………53
Figure 8.10 Pressure analysis of second model………………………………………………………………………..53

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TABLE LIST
Page
Table 4.1 Main dimensions of 20 different types of cargo ships……………………………….…………17
Table 4.2 L-DWT values of 20 types of cargo ships………………………………………………………………18
Table 4.3 L/B-DWT values of 20 types of cargo ships……………………………………………………..……18
Table 4.4 L/D-DWT values of 20 types of cargo ships…………………………………………………..………19
Table 4.5 B/T- DWT values of 20 types of cargo ships…………………………………………………………19
Table 5.1 Ship Offset Table for series 60…………………………………………………………………..…………20
Table 7.1 Non-Newtonian Flow……………………………………………………………………………………………37
Table 8.1 Number of iteration for first model………………………………………………………………………50
Table 8.2 Number of iteration for second model………………………………………………………………...51

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ABSTRACT
SHIP DESIGN AND ANALYSIS
Uğur CAN
İsmail Hakkı TOPAL
Department of Naval Architecture and Marine Engineering
Advisor: Assoc. Prof. Dr. Seyfettin BAYRAKTAR

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CHAPTER 1
INTRODUCTION
1.1 A Ship
A ship is a large buoyant watercraft. Ships are generally distinguished from boats based on size,
shape and cargo or passenger capacity. Ships are used on lakes, seas, and rivers for a variety of
activities, such as the transport of people or goods, fishing, entertainment, public safety, and
warfare. Historically, a "ship" was a sailing vessel with at least three square-rigged masts and a
full bowsprit.
Ships and boats have developed alongside humanity. In armed conflict and in daily life they
have become an integral part of modern commercial and military systems. Fishing boats are
used by millions of fishermen throughout the world. Military forces operate vessels for naval
warfare and to transport and support forces ashore. Commercial vessels, nearly 35,000 in
number, carried 7.4 billion tons of cargo in 2007. As of 2011, there are about 104,304 ships
with IMO numbers in the world.
1.2 A Cargo Ship
A cargo ship or is any sort of ship or vessel that carries cargo, goods, and materials from one
port to another. Thousands of cargo carriers ply the world's seas and oceans each year,
handling the bulk of international trade. Cargo ships are usually specially designed for the task,
often being equipped with cranes and other mechanisms to load and unload, and come in all
sizes. Today, they are almost always built of welded steel, and with some exceptions generally
have a life expectancy of 25 to 30 years before being scrapped.
General cargo vessels carry packaged items like chemicals, foods, furniture, machinery, motor-
and military vehicles, footwear, garments, etc.
Figure 1.1 Cargo ship

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CHAPTER 1
INTRODUCTION
1.3 Reasons of Building Ships
Ship are designed to fulfill some specific services and are manufactured. Ships are industrial
structures or platforms. Shipowners thinks ship design for some purpose. In generally, this
purposes are listed below.
 Making the renewal or renovations of the aging vessels.
 Increasing the number of ships in an existing commercial routes or increasing
commercial gain by making the modification of the vessel.
 Offer new service on an existing commercial routes or expand its market share by
carrying different loads.
 Opening new markets by offering a new type of transport or routes in changing
geopolitical and economic conditions.
 Performing industrial activities on offshore.
 Supporting to the commercial and industrial ships.
 to help the nation's maritime defense.
Ships are classified as follows according to the mission:
 Merchant Ships
 Industrial Ships
 Service Ships
 Warships

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CHAPTER 2
DESIGN
2.1 Design
Design as the creative component of engineering by which I mean that component in which a
new thing is created. A possible synonym for design is synthesis as distinct from analysis. In
engineering analysis a system is described, and the system's performance is estimated or
calculated by the application of engineering principles.
The development of any complex engineering system involves a natural conflict between
creativity/inventiveness and risk avoidance/conservatism. Gallin proposes some tentative
principles of inventiveness in ship design:
 an innovation should come out at the right moment
 not all inventions which have failed should be forgotten, some of these deserve
reconsiderations periodically
 most successful inventions do not suddenly appear on the market, they are the
result of step by step application of inventiveness in ship design
 shipowners do not like inventions (their daily task is already a risky business)
 do not include in a ship design more than one major invention at a time
 an invention to be acceptable in a ship design has to be first of all reliable
 to be reliable an invention has to be built up as far as possible of conventional
parts and has to be easy to maintain and repair, and that means it has to be simple
 an invention to be accepted by a shipowner should offer substantial economical
profit (to offset risk aversion)
 the profit of an invention should be presented in the most attractive manner for
the customer (evaluated from the shipowner’s viewpoint)
 a designer should not hang on the whole of an invention, he should accept
partial results or whatever comes out.
Although seagoing ships have been designed and built for a long time, the last few decades
have witnessed dramatic progress in ship design techniques. The most visible changes are the
ever-expanding applications of the computer. These embrace not only all levels of technical
design and analysis, but also incorporate production and operational considerations in the
design process.

14
CHAPTER 2
DESIGN
2.2 Design Spiral
The design of a ship is an iterative process, in which early estimates are made, and then
repeatedly corrected and developed as a consequence of feedback from subsequent steps.
Given the multifunctional nature of ships, they have many conflicting requirements which have
to be met to some degree. Thus the design problem is one of achieving a balanced and
adaptable solution, in which uncertainities have been minimised. Ballast may also be carried
aboard an aircraft. For example, in gliding it may be used to increase speed or adjust the
aircraft's center of gravity, or in a balloon as a buoyancy compensator.
There is no generally accepted sequential approach to represent the ship design process.
Inevitably, however, the adopted process encompasses making a large number of decisions,
with each descision or choice greatly affecting the next phase of the design. The adopted
process is often repeated with a greater degree of accuracy. The classical way of describing the
progressive convergence of the design process to a final configuration is a design spiral. The
design progresses in an orderly fashion through a system of processes that address each aspect
of ship geometry and ship performance. Within the design spiral concept, the iterative ship
design process is considered as a sequence of moves which gradually define the detail, and thus
achieves a balanced conclusion.
Figure 2.1 Design spiral

15
CHAPTER 3
DESIGN METHODS
3.1 General
Design and engineering methods can be subdivided in accordance with the different phases of
a typical newbuilding project. It all starts with the first feasibility ideas and through project
development phase we end up into the shipbuilding contract. The ship is defined with
specification, arrangement drawings, principal system diagrams and descriptions, architect
specification and documents, and with other possible technical documentation. A lot of
different kind of documentation is produced, but mainly without any simulations of the ship’s
main function, such as cargo handling, passenger flows, service and maintenance flows, safety
simulations and similar.
The next step after the contract is basic design and coordination engineering together with
procurement handling, master scheduling and build procedure planning. A lot of new parties
are introduced into the process and the problem seems to be the coordination. Even within the
design phase there are several parties involved and everybody is working within the same ship.
Coordination becomes the major issue not only technically but it is also time consuming. On the
other hand procurement requires good definitions of systems, areas, etc. to be purchased and
design work cannot proceed without information of these systems. Efficient coordination and
timing is required.
The next step is detail engineering, work planning and preparation including not only the yard’s
own work but also the work of different subcontractors and suppliers.
There are no general nor specific tools and methods available which could be used throughout
the different design and engineering steps, and even within each phase many different systems
are used without proper link and coordination between each other. A lot of time consuming
coordination problems arise.
There are generally several computer systems at shipyards and within the industry serving
shipping companies and shipyards. They are, however, typically tailormade systems and they
lack integration. Product data is spred out between different systems and companies without
common product model and thus the data in each system lives its own life. Coordination takes
time and in most cases the final coordination takes place only during the building and
installation phase, sometimes leading to rather costly solutions. There is also high bureaucracy
within the different systems and they support bureaucracy, not flexibility.

16
CHAPTER 3
DESIGN METHODS
3.2 3-D Computer Modelling
3-dimensional computer models are still mainly prepared to compensate the actual plastic
design models, i.e. the 3-D model is prepared to produce only workshop drawings. Most of the
models, modelling techniques, are specific forstructural design or piping design.
Models of complete vessels with all disciplines included are still rare. 3-D computer modelling
technique is not used at the project design stage. 3-D computer modelling technique should be
applied in accordance with the actual design procedure, i.e. starting from the project design
phase before the shipbuilding contract is even signed. The same model should then be
extended into a real product when design and engineering are proceeding.
Figure 3.1 Early project phase virtual model of a dry cargo ship

17
CHAPTER 4
MAIN DIMENSIONS
4.1 Design Requirements
There are two main design requirements in ship design. These are DWT and Vs. These two
features is the most important characteristics of merchant ships because ‘DWT and Vs’ give
ideas to us about load carrying capacity of ships.
In this project; DWT and Vs values specified for design requirements too. These two values
given below:
DWT=4900 tone
Vs=20 knots
Design requirements are important in terms of the other dimensions. After decided or given
design requirements, this values provide to determine the other main dimensions. Due to the
fact that, initially design requirements should be specified.
4.2 Determined Main Dimensions
As we stated, after design requirements specified, we can determine main dimension. There
are two ways of this process. Firstly, there are some empirical formulas for determining main
dimensions. The other way is regression analysis. This method used more than empirical
formulas in ship design.
4.3 Regression Analysis
In statistics, regression analysis is a statistical process for estimating the relationships among
variables. It includes many techniques for modeling and analysing several variables, when the
focus is on the relationship between a dependent variable and one or more independent
variables. More specifically, regression analysis helps one understand how the typical value of
the dependent variable changes when any one of the independent variables is varied, while the
other independent variables are held fixed. Most commonly, regression analysis estimates
the conditional expectation of the dependent variable given the independent variables that is,
the average value of the dependent variable when the independent variables are fixed. Less
commonly, the focus is on a quantile, or other location parameter of the conditional
distribution of the dependent variable given the independent variables. In all cases, the
estimation target is a function of the independent variables called the regression function. In
regression analysis, it is also of interest to characterize the variation of the dependent variable
around the regression function which can be described by a probability distribution.

18
CHAPTER 4
MAIN DIMENSIONS
In regression analysis, choosen 20 types of cargo ships and noted their main dimensions.
(L,B,D,T etc.) Then created different graphs belong to this dimensions and our design
requirements. After created this graphs, determined the other main dimensions by using
regression analysis. This main dimensions are belong to our ship. After that completed
calculations of main dimensions.
Table 4.1 Main dimensions of 20 different types of cargo ships

19
CHAPTER 4
MAIN DIMENSIONS
4.4 Tables of Regression Analysis
Table 4.2 L-DWT values of 20 types of cargo ships
 According to this table L is finded out; L=98,527
Table 4.3 L/B-DWT values of 20 types of cargo ships
 According to this table L/B is finded out; L/B= 6,4066
 L was finding out; L=98,527 so B=15,37898
y = 0.002x + 88.62
0
20
40
60
80
100
120
140
4650 4700 4750 4800 4850 4900 4950 5000 5050
L-DWT
y = 0.000x + 5.416
0
1
2
3
4
5
6
7
8
9
10
4650 4700 4750 4800 4850 4900 4950 5000 5050
L/B-DWT

20
CHAPTER 4
MAIN DIMENSIONS
Table 4.4 L/D-DWT values of 20 types of cargo ships
 According to this table L/D is finded out; L/D=14,607
 L was finding out; L=98,527 so D= 6,745191
Table 4.5 B/T- DWT values of 20 types of cargo ships
 According to this table B/T is finded out; B/T=2,783
 B was finding out; B=15,37898 so T=5,526045
y = 0.005x - 14.10
0
5
10
15
20
25
30
4650 4700 4750 4800 4850 4900 4950 5000 5050
L/D-DWT
y = 0.000x - 0.187
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
4650 4700 4750 4800 4850 4900 4950 5000 5050
B/T-DWT

21
CHAPTER 5
DESIGN OF A CARGO SHIP
5.1 Main Dimensions
5.2 Offset Table
WL0 WL0,3 WL1 WL2 WL3 WL4 WL5 WL6
0(A.P.) 0 0 0 0 0 0,68975 2,2165 3,3945
0,5 0,137175 0,5022 0,6882 0,82925 1,271 2,852 4,433 5,456
1 0,46035 1,37795 1,894875 2,4335 3,29375 4,7585 5,92875 6,6185
2 2,0553 3,660325 4,67945 5,6265 6,39375 6,95175 7,3625 7,6105
3 4,2129 5,848925 6,8603 7,41675 7,595 7,68025 7,7345 7,75
4 5,741975 7,0184 7,64925 7,75 7,75 7,75 7,75 7,75
5 5,97525 7,1765 7,7345 7,75 7,75 7,75 7,75 7,75
6 5,963625 7,1765 7,7345 7,75 7,75 7,75 7,75 7,75
7 4,959225 6,430175 7,285775 7,52525 7,595 7,63375 7,6725 7,688
8 2,610975 4,4857 5,60015 6,0295 6,2155 6,40925 6,59525 6,79675
9 0,597525 1,908825 2,707075 3,01475 3,15425 3,3325 3,658 4,154
9,5 0,155 0,789725 1,222175 1,37175 1,426 1,5035 1,77475 2,31725
10(F.P.) 0 0 0 0 0 0 0,155 0,39525
Table 5.1 Ship Offset Table for series 60
L= 98,5
B= 15,5
D= 6,7
T= 5,5

22
CHAPTER 5
5.3 Drawings first cargo ship:
 Drawing Sections of the ship
Figure 5.1 Sections of the ship
 Drawing buttock plane of the ship
Figure 5.2 Profile view of the ship

23
CHAPTER 5
 Drawing water lines of the ship
Figure 5.3 Water lines of the ship
 Perspective view of the ship
Figure 5.4 Perspective view of the ship in Maxsurf

24
CHAPTER 5
Figure 5.5 Perspective view of the ship in Rhino
 Generally Drawings
Figure 5.6 Generally drawings in Rhino

25
CHAPTER 5
5.4 Drawing of second cargo ship
 Drawing sections of the ship
Figure 5.7 Section view of the ship
 Drawing buttock plane of the ship
Figure 5.8 Profile view of the ship

26
CHAPTER 5
 Drawing water lines of the ship
Figure 5.9 Drawing water lines of the ship
Figure 5.10 Perspective view of the ship

27
CHAPTER 6
ANALYSIS
6.1 Hydrostatic values about first ship
Figure 6.1 Hydrostatic values of first ship

28
CHAPTER 6
ANALYSIS
6.2 Hydrostatic values of second ship
Figure 6.2 Hydrostatic values of second ship

29
CHAPTER 6
ANALYSIS
6.3 Resistance values that affect to first ship:

Figure 6.3 Effective Power- Speed Graphic

Figure 6.4 Total Resistance Coefficient-Speed Graphic

30
CHAPTER 6
ANALYSIS

Figure 6.5 Residuary Resistance Coefficient-Speed Graphic

Figure 6.7 Wave Resistance Coefficient-Speed Graphic

31
CHAPTER 6
ANALYSIS

Figure 6.8 Friction Resistance Coefficient-Speed Graphic

Figure 6.9 Viscous Resistance Coefficient-Speed Graphic

32
CHAPTER 6
ANALYSIS

Figure 6.9 Correlation Coefficient-Speed Graphic

33
CHAPTER 7
COMSOL
7.1 Introduction
Read this chapter if you are new to COMSOL Multiphysics. It provides a quick overview of
the COMSOL environment with examples that show you how to use the COMSOL Desktop user
interface and the Model Builder.
7.2 CFD Module
Figure 7.1 Comparison of the flow field in a 2D approximation with the 3D model of a
baffled, turbulent reactor.

34
CHAPTER 7
COMSOL
7.3 Physics Interfaces Appropriate for Any Type of Flow
Tools for defining the different descriptions for fluid flow are packaged and available in easy-
to-use physics interfaces. Under the hood, these interfaces define the conservation of
momentum, mass, and energy equations that describe fluid flow, accounting for the
contribution from multiphysics couplings to other physics. Furthermore, they formulate a
stabilized form of these equations, which can be used by COMSOL to create finite element
discretization for space and finite differences for time derivatives for stationary or time
dependent problems. The stabilized formulations are adapted to the selected description and
the functions for the fluid properties by the physics interfaces, which also suggest solver
configurations and solver settings for the type of flow described. Tailor-made physics interfaces
are available for the following types of fluid flow:
7.3.1 Single-Phase Flow
The CFD Module solves multiple variations of the Navier-Stokes equations to model flows in
all velocity regimes. This includes the modeling of low-velocity fluids, or creeping flow (Stokes
flow), laminar and weakly-compressible flow, and turbulent flow. Turbulent flow is modeled
using the Reynolds-Averaged Navier-Stokes (RANS) equations and includes the k-ε, low-
Reynolds k-ε, k-ω, SST (Shear Stress Transport), and Spalart-Allmaras turbulence models.
You have the option to manipulate all of the variables in the Navier-Stokes equations and the
terms in the turbulence models. You can, for example, include equations based on model
variables from other coupled physics interfaces. Many additional tools exist for assisting in the
solution process of turbulence models. Among these are tools for the specification of wall
functions, including wall roughness, automatic boundary layer meshing, hybrid meshes, and
other tools for adapting mesh density and placement.
7.3.2 Nonisothermal Flow
Thermally-induced buoyancy forces are considered by default in both laminar and turbulent
flows when coupled to heat transfer. The CFD Module includes ready-made multiphysics
interfaces for nonisothermal and conjugate heat transfer. The module can combine arbitrary
multiphysics couplings to define weakly compressible flows, i.e. flows with Mach numbers
below 0.3.
7.3.3 Compressible Flow
The CFD Module is also able to model compressible fluids for Mach numbers greater than
0.3, where temperature variations caused by heat transfer, compression work, or work done by
friction forces, result in significant compressibility effects, like shocks, for instance. The built-in

35
CHAPTER 7
COMSOL
adaptive meshing capabilities within COMSOL Multiphysics help greatly with resolving shock
waves and areas of great change in the fluid flow profile.
7.3.4 Two-Phase Flow
Physics interfaces and supporting equations are at your disposal for modeling two-phase
flow. When this includes tracking the moving interfaces separating two or more immiscible
fluids, the CFD Module utilizes the Phase Field and Level Set methods.
The CFD Module also includes physics interfaces for dispersed two-phase fluid flow models for
describing flows that contain suspensions of many particles, droplets, or bubbles through the
Bubbly Flow, Mixture Model, and Euler-Euler Model methods. The latter method handles high
concentrations of bubbles that collide frequently and contain significant variations in relative
velocity between the phases. The Heat Transfer Module also includes interfaces for the
modeling of condensation and humid air, where phase changes are described using built-in
step functions in COMSOL Multiphysics.
7.3.5 Porous Media Flow
With the CFD Module, you can also model the transport of single-phase and two-phase
fluids in porous media, by utilizing Darcy's Law and Brinkman's extension to Darcy's Law.
Darcy's Law is appropriate for porous media where the pores are small enough to negate
viscous effects, so that flow is driven by a pressure difference, while the Brinkman equations
include terms accounting for viscous effects. An internal condition also exists that allows for
modeling the interface between free channel fluid flow and the porous media.
7.3.6 Rotating Machinery
The Rotating Machinery interfaces include modeling tools to describe rotating parts that
dynamically change the geometry, such as the vanes in a mixer or fins in a propeller rotating in
a fluid domain. There is also a Frozen Rotor interface that approximates the rotation by
including additional terms in the fluid flow equations instead of changing the geometry during
the simulation. Using far less computational resources than solving for the actual rotation, this
physics interface adds centrifugal or coriolis forces to the formulation of the stationary Navier-
Stokes equations, and provides good approximations for modeling applications like turbines,
centrifugal separators, and mixers. An interface for Swirl Flow is also available for modeling
rotating flows. In this physics interface, an out-of-plane swirl velocity component is included for
axisymmetric models yielding a three-dimensional velocity vector defined in a 2D geometry,
which also reduces computational requirements compared to full 3D modeling.

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CHAPTER 7
COMSOL
Figure 7.2 Flow field in a stirred, baffled mixer using the Rotating Machinery interface.

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COMSOL
7.3.7 Thin-Film Flow
A specialized physics interface is included in the CFD Module to model the flow of liquids or
gases confined in thin layers between two surfaces, or on the one surface, for example to
model lubrication.
7.3.8 Non-Newtonian Flow
The CFD Module includes the Carreau and Power-Law models, but also allows you to define
your own equations or bring in external data to describe the viscosity and shear rate of polymer
and other non-Newtonian fluids. You may, for example, define viscoelastic models in this way.
Step functions are built into COMSOL Multiphysics, and can be utilized for modeling large or
sudden changes in the fluid properties, for example to describe Bingham fluids.
Table 7.1 Non-Newtonian Flow: The shear rate, dynamic viscosity and volumetric flow of a
polystyrene solition and the volumetric flow for an equivalent Newtonian fluid.

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CHAPTER 7
COMSOL
7.3.9 Flow Through Thin Screens
Modeling processes that include perforated plates, grilles, and wire-gauzes are made easier
using the built-in Thin Screens feature. This includes correlations for refraction and resistance
coefficients that consider the effects of flow through a screen, and before and after a screen for
laminar or turbulent flow.
7.3.10 Fluid Flow and Heat Transfer
The CFD Module includes a Conjugate Heat Transfer interface for describing fully coupled
heat transfer in solids and fluids, including laminar and turbulent fluid flow. By default, this
solves for nonisothermal flow and can be coupled to any other physics interface that includes
temperature, such as interfaces for surface-to-surface radiation in the Heat Transfer Module,
Joule heating, and heat of reactions in Chemical Species Transport interfaces. In addition,
physics interfaces for heat transfer in porous media combine the conduction in the solid matrix
to the conduction and convection in the fluid phase while accounting for the tortuous path
taken by the fluid, and the heat dispersion this entails.
7.3.11 Reacting Flow
A specialized interface that couples both laminar and turbulent flow to the transport of
chemical species in dilute and concentrated solutions is included, and you can couple it with
interfaces that describe chemical reaction from the Chemical Reaction Engineering Module
7.4 Simulation Software for All Fluid Flow Applications
The CFD Module is the platform for simulating devices and systems that involve
sophisticated fluid flow models. As is the case with all modules in the COMSOL Product Suite,
the CFD Module provides ready-made physics interfaces that are configured to receive model
inputs via the graphical user interface (GUI), and to use these inputs to formulate model
equations. The particular physics interfaces that the CFD Module is equipped with enable you
to model most aspects of fluid flow, including descriptions of compressible, nonisothermal,
non-Newtonian, two-phase, and porous media flows – all in the laminar and turbulent flow
regimes. The CFD Module can be used as a standard tool for simulating computational fluid
dynamics (CFD), or in collaboration with the other modules in the COMSOL Product Suite for
multiphysics simulations where fluid flow is important.
The CFD Module GUI grants you full access to all steps in the modeling process. This includes
the following steps:
 Selecting the appropriate description of the flow, for example single-phase or two-phase,
laminar or turbulent flows, etc.
 Creating or importing the model geometry
 Defining the fluid properties

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COMSOL
 Adding source and sink terms, or editing the underlying equations of the fluid model, if
required
 Selecting mesh elements and controlling the density of the mesh at different positions
 Selecting solvers and tuning them, if required
7.5 Unified Platform for Multiphysics and Multidisciplinary Simulations
Flow is an integral part of many different processes and applications, and must be
understood and optimized often with respect to how it affects other processes. The effective
cooling of a computer’s hard drive, the dispersion of energy within the damping film of an
accelerometer, and the transport of species through the different parts of a chemical reactor
are examples where fluid flow is a contributor to a process described by other physics. Yet, in
reality, the heat emanating from the electronic devices affects the fluid's density. The
accelerometer's elasticity imposes an oscillation on the flow, and the reactions change chemical
composition and potentially the fluid flows' driving pressure. This means that you must also
include their effects for a completely accurate description of the overall process.
COMSOL Multiphysics and the CFD Module help in describing such processes through the
seamless coupling of all involved physics, and through allowing unhindered access to the model
equations directly in the GUI. Also at your disposal are the two-way coupled fluid structure
interaction (FSI) formulations. These allow you to model scenarios where the fluid deforms a
structure, and where this structure's reaction to its deformation in turn influences the fluid
flow. All the physics interfaces in the CFD Module can be coupled with any of the other
modules in the COMSOL Product Suite to provide the standard platform for applications where
computational fluid dynamics need to be considered.
COMSOL also provides modules that model flow in alternate ways to the CFD Module, but
which can still be easily coupled to utilize the benefits from both. One example of this is
the Pipe Flow Module, which models fully developed flow in 2D and 3D piping networks using
edge elements, with one tangential average velocity component along the edges, for describing
the pipe sections. This allows you to model flow in a pipe network connected to tanks in a
process, but avoid meshing the cross section of the pipes in the network, which would result in
large 3D meshes. COMSOL contains a feature that seamlessly allows the mapping of data from
edges, to surfaces, and volumes, and vice versa, to connect pipe networks to fully meshed 2D
or 3D geometries. In this way, you can consider the computational fluid dynamics properties of
a certain unit within a whole network of piping, and adjust the operating conditions of both in
connection to each other.
Since all physics are modeled using the same, standard graphical user interface and
workflow, CFD engineers can easily communicate with other engineers analyzing different
characteristics of the same component or process, such as structural, electrical, or chemical
properties. All you have to do is send over the file, switch off the physics not being investigated,
add another physics interface or two, and continue modeling. And, of course, couple these new

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CHAPTER 7
COMSOL
physics interfaces to the one describing fluid flow for a full multiphysics simulation of the
component or process.
7.6 Approaching Your Final CFD Solution in Steps
Simulating computational fluid dynamics in equipment or processes is often a workflow where
you approach a final, accurate solution in steps. The CFD Module contains many different tools,
features, settings, and interfaces to assist you through all the steps of your workflow.
The CAD Import Module or one of the LiveLink™
products assists you in bringing in the geometry
of your part, component, or process to be simulated from a third-party CAD software. These
products allow you to subsequently manipulate your geometry to help reduce small features
and artifacts that may not be important for the flow, but that complicate the meshing of CFD
simulations.
Once you have your 3D CAD design within the CFD Module, you may not want to immediately
launch yourself into performing 3D simulations. COMSOL Multiphysics supports the ability to
create a 2D modeling workspace from 3D geometries. By working on a 2D geometry, such as a
representative cross section, you will be able to familiarize yourself with a number of the
parameters in your simulation. Without using the large computational resources that a 3D
model would require, you can:
 Investigate the effect fluid properties have on the overall simulation
 Decide what the appropriate turbulence model to use is
 Determine the placement of appropriate meshing and boundary layer meshing
 Select the solvers and settings to use
 Study the effects of multiphysics couplings on the fluid flow
 Estimate the accuracy you may expect from a 3D model
With a greater understanding of your system, you can then perform the full 3D simulation
using the knowledge and optimized settings gained from the 2D model. This feature is also
especially useful for treating 3D CAD designs that are symmetric or axisymmetric, avoiding 3D
modeling altogether, and reducing the computational requirements substantially.
7.7 Tools for Providing Flexibility within Meshing and Robust Solving
Meshing is often a critical step in modeling computational fluid dynamics in devices or
processes. The mesh must be good enough to provide accuracy, but not too fine so as to drain
computational resources. COMSOL Multiphysics provides many different tools to ensure a good
mesh for fluid flow simulations. This includes creating unstructured, structured and swept
meshes, which allow for flexibility in considering the modeling domain's geometric dimensions
and their ratio, and the effects on the flow's directions. The CFD Module also utilizes boundary
layer meshing to insert structured layers of mesh along boundaries such as walls, and integrate
them into surrounding structured or unstructured meshes to become an overall hybrid mesh.

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COMSOL
The CFD Module makes use of most of the linear, nonlinear, time-dependent, and
parametric solvers found within COMSOL Multiphysics. This includes direct solvers for solving
2D and small 3D models, which have good abilities to easily converge, and iterative solvers for
larger or more complex models. Preconditioning and multigrid solvers are available to work in
collaboration with other solvers to ensure solutions. Advanced solver functionality, such as the
inclusion of crosswind and streamline diffusion, and smoothing methods, are available, and
their values can be fine-tuned along with most of the other solver settings. The CFD Module
also utilizes elements of different orders in one and the same simulation, and may apply lower
order elements to solve one variable, such as pressure, and higher order elements to solve the
other variables.
The solver scheme also allows for better approximations of initial values for a solving
process. This includes setting up solver schemes that will solve for an easier description of flow,
such as the laminar flow field within a certain modeling domain, and apply this solution as the
initial guess to a turbulent flow description. A solution using the Frozen Rotor interface can be
used as the initial guess to a full simulation of the rotating modeling domain, saving you a lot of
computational resources.
7.8 Extract Accurate and Descriptive Data from CFD Simulations
The CFD Module calculates properties intrinsic to fluid flow, such as: flow patterns; pressure
losses; forces on objects subjected to flow, drag, and lift; temperature distribution; and
variations in fluid composition in a system. Moreover, it provides qualitative postprocessing
involving surface, streamline, ribbon, arrow, and qualitative particle tracing plots as well as
animations. Data from all parameters and variables in the underlying equations, and extra
terms are accessible to be extracted and plotted against any other parameter or variable. This
includes postprocessing derived values, like drag and lift coefficients. By including and coupling
physics from the Particle Tracing Module in the solving of your CFD applications, you can
consider the effects of particles on both the flow itself (Lagrange-Euler), and on each other,
through collisions and their own momentum.

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COMSOL
7.9 COMSOL Desktop

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COMSOL
7.10 Creating a New Model
You can set up a model guided by the Model Wizard or start from a Blank Model as shown in
the figure below.
7.10.1 Creating a Model Guıded By The Model Wizard
The Model Wizard will guide you in setting up the space dimension, physics, and study type in a few
steps:
 Start by selecting the space dimension for your model component: 3D, 2D Axisymmetric, 2D, 1D
Axisymmetric, or 0D.

45
CHAPTER 7
COMSOL
 Now, add one or more physics interfaces. These are organized in a number of Physics
branches in order to make them easy to locate. These branches do not directly
correspond to products. When products are added to your COMSOL Multiphysics
installation, one or more branches will be populated with additional physics interfaces.
 Select the Study type that represents the solver or set of solvers that will be used for the
computation.
Finally, click Done. The desktop is now displayed with the model tree configured according to the
choices you made in the Model Wizard.

46
CHAPTER 8
CFD ANALYSIS IN COMSOL
8.1 First Modelling:
 First model which like a pontoon:
Figure 8.1 First model like a pontoon which has ship’s dimensions
 First towing tank with pontoon:
Figure 8.2 First towing tank and pontoon

47
CHAPTER 8
8.2 First Analysis:
After modelling part, models meshed, boundary conditions and initial values determined
and analysis started.
 Meshing model and towing tank:
Figure 8.3 Normal size meshing mdel and towing tank

48
CHAPTER 8
 Velocity Analysis of First Model:
Figure 8.4 Velocity analysis of model
 Pressure Analysis of First Model:
Figure 8.5 Pressure analysis of model.

49
CHAPTER 8
 Iteration Number for Convergence:
Table 8.1 Number of iteration for first model

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CHAPTER 8
8.3 Second Modelling:
 Second cylindirical model:
Figure 8.6 Sylindirical Model
 Second towing tank with sylindirical model:
Figure 8.7 Second towing tank and sylindirical model

51
CHAPTER 8
8.4 Second Analysis:
After modelling part, models meshed, boundary conditions and initial values determined
and analysis started.
 Meshing model and towing tank:
Figure 8.8 Coarse size meshing model and towing tank

52
CHAPTER 8
 Velocity Analysis of Second Model:
Figure 8.9 Velocity analysis of second model
 Pressure Analysis of First Model:
Figure 8.10 Pressure analysis of second model

53
CHAPTER 8
 Iteration Number for Convergence:
Table 8.2 Number of iteration for second model

54
CONCLUSION
In the end of the project we could learn how to design a cargo ship. Finding main
dimensions, drawing ships model, calculating result of analysis.

55
REFERENCES
[1] http://www.workboatsinternational.com/
[2] Maritime Engineering Handbook
[3] http://www.turbosquid.com/
[4] http://www.creativecrash.com/
[5] http://www.law.uchicago.edu/files/files/20.Sykes_.Regression.pdf
[6] http://www.nap.gr/ship-design.html
[7] http://ittc.sname.org/
[8] http://www.marinewiki.org/
[9] https://tez.yok.gov.tr/UlusalTezMerkezi/
[10] International Journal of Computational Fluid Dynamics
[11] http://www.researchgate.net/profile/Tao_Xing/publication/
Computational_Towing_Tank_Procedures
[12] http://www.engr.mun.ca/~bveitch/courses/r-p/Assignments/ITTC-calculation-
procedures-Lab1.pdf
[13] https://www.amc.edu.au/maritime-engineering/towing-tank
[14] http://www.simman2008.dk/PDF/7.5-02-06-
02%20%28captive%20model%20tests%29.pdf
[15] IIHR – Iowa Institute of Hydraulic Research
[16]http://www.researchgate.net/profile/Daniele_Peri2/publication/233560163_Design_Op
timization_of_Ship_Hulls_via_CFD_Techniques/links/0deec53849fc25609f000000.pdf

56
CURRICULUM VITAE
PERSONAL INFORMATION
Name Surname
: Uğur CAN
Date of birth and place : 23/07/1993 / Dernbach
Foreign language : English
E-mail : ugurr.can93@gmail.com
PERSONAL INFORMATION
Name Surname
: İsmail Hakkı Topal
Date of birth and place : 06/10/1992 / Bakırköy
Foreign language : English
E-mail : ismailhakkitopal@gmail.com

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