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 McCormick and Bhattchara (1973)- injected

micro-bubbles into turbulent boundary layer

Literature Review Takahashi (2000)- determined that micro-

bubble placement is essential

Literature Review Shen et al. (2006)- determined that micro-

bubble size plays an important role in drag reduction

Literature Review 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

Top View

Force= Mass(Acceleration)

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