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Estimation of Ship Resistance
School of Internet Program 06.01.2009
Estimation of Ship Resistance from model Experiment
Faculty of Marine Technology TokyoFaculty of Marine Technology Tokyo University of Marine Science and
Technology
Shoji Kuniaki
Kuniaki ShojiDepartment of Marine System Engineering
Faculty of Marine Technology
Tokyo University of marine Science and Technology
1970 graduate Yokohama National University (Department of Naval Architecture, Faculty of Engineering)
1975 graduate the Doctoral course of the University of Tokyo
Doctoral Thesis: The study of motion of Mooring Ship and Tension of Mooring Line
researching theme
Protective Systems of The Bridge Pier against Ship collision
Performance of Anti-rolling Tank
Study on High holding power anchor
Development of the city of waterfront
History of ship
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Outline of this Lecture
• In this lecture Froude’s method is explained. This is a estimation method which evaluate s s a est at o et od w c eva uateactual ship resistance from model experiment.
• At First the component of resistance is shown and explained. Next, model experiment at the so called towing tank which is executed
i i i d d A h lresistance test is introduced. As these results, estimation method of actual ship resistance so called Froude’s method is explained.
Components of Ship Resistance• Total Resistance = Water Resistance + Air Resistance• Water Resistance = Frictional Resistance + EddyWater Resistance Frictional Resistance + Eddy
Resistance + Wave Making Resistance• Water Resistance = Frictional Resistance + Residuary
Resistance• Water Resistance = Viscous Resistance + Wave Making
ResistanceResistance• Residuary Resistance = Eddy Resistance + Wave Making
Resistance• Viscous Resistance = Frictional Resistance + Eddy
Making Resistance
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Wave making resistance
Resistance Test by model
It is difficult to estimate ship resistance by only theoretical calculationby only theoretical calculation.
Then it is experimented now at the experimental tank, so called SHIP MODEL BASIN, SHIP TOWING TANK .
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William Froude• 1810年~1879年
• Who Called the Father of Modern NavalWho Called the Father of Modern Naval Architecture
• From Experience to theory • Estimation of Actual Ship Resistance from
Model Experiment(Froudes’ Method)Model Experiment(Froudes Method)
• Froude Number Fn=V/(gL)1/2
• Method of Model Experiment• Construction of Towing Tank
Towing Tank
• Towing Tank of Yokohama National• Towing Tank of Yokohama National University(Japan)
• Berlin Model Basin(Germany)
• Which facilities are there?• How experiment there?
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Profile of Yokohama University Ship Model Basin
Dimensions of Yokohama University Ship model Basin
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Control Room and Resistance Dynamometer
Resistance Dynamometer
Resistance DynamometerBalance
measurement
id
Trim measurementTrim measurement
Towing Carriagey
Ship model
guide
Towing Rod
Counter Weight
guide
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Towing Tank at Torquay
Towing TankYokohama Tokyo Berlin TorquayNational University Model TowingUniversity Marine S. Basin Tank
TechnologyLength 110m 54m 250m 59.44m
Breadth 8m 10m 8m 10.98m
Depth 3.5m 2m 4.8m 3.05m
Speed 4.0m/s 1.2m/s 9.0m/s 5.08m/s
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Experiment of Actual Ship
Experiment of Greyhound
E i f Pl k ShiExperiment of Plank Ship
Experiment of Yudachi
Evaluation of Actual Ship• Training Ship of Faculty of Marine technology
「SHIOJI MARU Ⅲ」
• Length:Ship=46m Model=1 5m• Length:Ship=46m、 Model=1.5m• Scale 1/30.6• Model Measurement V=1.0m/s ⇒RTM=0.2kg• Resistance of Ship RTS
0 2k ×30=6k ?0.2kg×30=6kg ?
0.2kg×302=180kg ?
0.2kg×303=5400kg=5.4t ?
Speed of Actual Ship =1.0m/s ?
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Froude’s Method• Water Resistance divides two components.
(Water Resistance=Frictional Resistance+Residuary Resistance)
• Frictional Resistance of ship and model equals Frictional resistance of flat plate.(However that length、wetted surface area、surface condition are same.)
• Resid ar resistance of ship and model is• Residuary resistance of ship and model is proportional to 3 times of scale.(However speed of ship and model is proportional to root of scale.) (Froude’s low of Comparison)
Resistance Test of model of Shioji maru Ⅲ
• Corresponding speed:model 1.0m/sship 1 0m/s×301/2=5 5m/sship 1.0m/s×30 5.5m/s
• Frictional Resistance:from resistance of platemodel 0.1kgship 1.5t
• Resistance test :water resistance 0.2kgg• Residuary resistance of model 0.2-0.1=0.1kg• Residuary resistance of ship 0.1×303=2700kg
=2.7t• Water Resistance of Ship 1.5+2.7=4.2t
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Water resistance of shipResistance coefficient
model
ship
Reynolds number
Evaluation of Ship Resistance
Ship resistance
Estimation 1
Estimation 2
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Quiz• (1)Man who estimate the ship resistance
from model experiment. • (2)The place where towing tank was made
at first.• (3)The ships name of experiment of
resistance at first.• (4)Biggest instrument of the world in
Berlin Model Basin.• (5)please comment : [email protected]
Thank you for your kind attention