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Improving Hydrodynamic Efficiency through the Application of a Bulbous Bow and Micro Bubbles

Improving Hydrodynamic Efficiency through the Application of a Bulbous Bow and Micro Bubbles. Harrison DiGia Advanced Science Research Period 7. Need. World Carbon Dioxide Emissions by Region, 2003-2030 (Billion Metric Tons of Carbon Dioxide).

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Improving Hydrodynamic Efficiency through the Application of a Bulbous Bow and Micro Bubbles

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  1. Improving Hydrodynamic Efficiency through the Application of a Bulbous Bow and Micro Bubbles Harrison DiGia Advanced Science Research Period 7

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

  3. 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

  4. Micro-Bubbles http://www.newscientist.com/data/images/archive/2539/25391601.jpg

  5. Literature Review • Drag Reduction of a Submersible Hull by Electrolysis (Naval Engineers Journal) • McCormick and Bhattchara (1973)- injected micro-bubbles into turbulent boundary layer

  6. Literature Review • Mechanisms and Scale Effects of Skin Friction Reduction by Microbubbles (Ship Research Institute) • Takahashi (2000)- determined that micro-bubble placement is essential

  7. Literature Review • Influence of Bubble Size on Drag Reduction (Experiments in Fluids) • Shenet al. (2006)- determined that micro-bubble size plays an important role in drag reduction

  8. Literature Review • Bulbous Bow Design Optimization for Fast Ships (Naval Architecture) • Kyriazis(1988)- tested different variations of a bulbous bow Effect of Bulb Diameter (D) on Total Resistance Effect of Bulb Length (L) on Total Resistance

  9. Engineering Goals Examine: • 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

  10. Methodology Improving Hydrodynamic Efficiency Through Methods of Active and Passive Flow Control Normal Ship n=5 Attach Bulbous Bow n=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

  11. Ship Drag Measurement Calculator Pasco Photogate and Pulley- Measures Acceleration Side View Mass Bulbous Bow Porous Plate Force = Acceleration X Mass

  12. Ship Drag Measurement Calculator Top View Mass

  13. Budget

  14. 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

  15. Bibliography

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