Improving Hydrodynamic

Efficiency through the Application of a Bulbous Bow and

Micro BubblesHarrison DiGia

Advanced Science ResearchPeriod 7

Need

90% of all goods that were sent around the globe went by ship (Kodama, 2006)

843 million tons of CO2 were released by international shipping in 2007

http://www.eia.doe.gov/bookshelf/brochures/greenhouse/Chapter1.htm

World Carbon Dioxide Emissions by Region,2003-2030 (Billion Metric Tons of Carbon Dioxide)

Bulbous Bow Protrudes just below the waterline

Reduces shock wave

Ideal for large ships

http://www.globalsecurity.org/military/systems/ship/images/bulbous-bow-image08.jpg

Micro-Bubbles

http://www.newscientist.com/data/images/archive/2539/25391601.jpg

Literature Review Drag Reduction of a Submersible Hull by

Electrolysis (Naval Engineers Journal)

McCormick and Bhattchara (1973)- injected micro-bubbles into turbulent boundary layer

Literature Review Mechanisms and Scale Effects of Skin

Friction Reduction by Microbubbles (Ship Research Institute)

Takahashi (2000)- determined that micro-bubble placement is essential

Literature Review Influence of Bubble Size on Drag Reduction

(Experiments in Fluids)

Shen et al. (2006)- determined that micro-bubble size plays an important role in drag reduction

Literature Review Bulbous Bow Design Optimization for Fast Ships

(Naval Architecture)

Kyriazis (1988)- tested different variations of a bulbous bow

Effect of Bulb Length (L) on Total Resistance

Effect of Bulb Diameter (D) on Total Resistance

Engineering GoalsExamine:

Changes in drag force caused by the application of a bulbous bow

Changes in drag force caused by the insertion of microbubbles

Improve hydrodynamic efficiency by using methods of passive and active flow control

Purpose

MethodologyImproving Hydrodynamic Efficiency Through Methods of Active and Passive Flow Control

Normal Shipn=5

Attach Bulbous Bown=1

Inject Micro-Bubbles in Water

(200-400 micrometers)n=1

Attach Bulbous Bow and Inject Micro-Bubbles

n=1

Inject Micro-Bubbles in 20 ppm Triton-X

(200-400 micrometers)n=1

Attach Ship to Ship Drag Measurement Calculator

Record mass and acceleration to calculate the drag force

Analyze force data using ANOVA (p<.05) followed by a Scheffe Post Hoc Test

Ship Drag Measurement Calculator

Mass

Pasco Photogate and Pulley- Measures Acceleration

Bulbous BowPorous Plate

Side View

Force = Acceleration X Mass

Ship Drag Measurement

CalculatorTop View

Mass

Item Vendor Category # Size Quantity Price

Triton-X Promega H5141 500mL 2 $79.99

Pourous Plates ICT International 0604D04-B15M1 5in radius 5

Micro Acquarium Bubbler Rena 17163057048 2in 1 $4.44

Pasport High Resolution Force Sensor Pasco PS-2189 1 $139.00

Photogate and Pulley System Pasco ME-6838 $80.00

Wood Home Depot

Water Tunnel Lab

Boat Lab

Air Injector Lab

$303.43

Budget

Do-ability Water tunnel in lab

Boat is already made

Micro-bubbles can be created using a simple aquarium bubbler

Bulbous bow can easily be inserted into front of model ship

Bibliography