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Enhancing Boat Efficiency: Micro Bubbles and Bulbous Bow Impact

This study investigates the effects of micro bubbles and bulbous bows on the aerodynamic efficiency of boats. With $438 million spent annually on boating fuel and 99.8% of goods transported by ships, optimizing fuel efficiency is crucial as carbon dioxide emissions rise. The research includes examining drag reduction techniques by employing micro bubbles in boundary layers and incorporating bulbous bows to reduce shock wave impact and friction drag. Experimental setups involve a water tunnel to measure performance improvements, analyzed through statistical methods.

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Enhancing Boat Efficiency: Micro Bubbles and Bulbous Bow Impact

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  1. The Effect of Micro Bubbles and Bulbous Bow on the Aerodynamic Efficiency of a Boat Harry Kucharczyk

  2. Need • $438 Million spent on annual boating fuel (Lipton 95) • 99.8% of goods are transported by ships • Carbon Dioxide emissions continue to rise www.unido-ichet.org

  3. Knowledge Base Bulbous Bow • Reduces shock wave • Decrease in friction drag http://www.globalsecurity.org www.marinefirefighting.com

  4. Knowledge Base Micro Bubbles • Inserted in the boundary layer • Decreased viscosity and density of the fluid www.impactlab.com

  5. Literature Review • McCormick and Bhattchara (73)- injected hydrogen micro bubbles into the turbulent boundary layer • Madavan (84)- location and distribution of bubbles are essential • Kato (94)- determined reduced skin friction drag by 80% through the use of micro bubbles • Kodama (00)- performed experiments in a water tunnel with microbubbles generated in an air injection chamber by injecting air through a porous plate

  6. Engineering Goals • Examine the effects of passive and active flow in boat drag reduction Purpose • Reduce skin friction drag by using methods of passive and active flow control

  7. Normal Boat n=2 Boat with Bulbous Bow n=2 Insert Microbubbles in the Boundary Layer using a porous plate (200-400 micrometers) Measure mass and acceleration to calculate the force Analyze data using SPSS One Way ANOVA and a Scheffe post Hoc test.

  8. Experimental Setup Bulbous Bow Porous Plate

  9. Newton’s Second Law Force = Mass X (Velocity1 – Velocity2) (Time1 – Time2) Force = Acceleration X Mass

  10. Do Ability • Water Tunnel is accessible in the lab • Boat has already been constructed • Bulbous bow can easily be inserted into the boat • Microbubbles can be made through simple appliances

  11. Budget

  12. Bibliography • Culley, Dennis. "Active Flow Control Laboratory." NASA - Active Flow Control. NASA. 29 Feb. 2008 <http://www.grc.nasa.gov/cdtb/facilities/flowcontrollab.html>. • Donovan, John, and Linda Kral. "Active Flow Control Applied to an Airfoil." American Institute of Aeronautics (1998). • Kato, H., Miyanaga, M., Haramoto, Y. & Guin, M. M. 1994 Frictional drag reduction by injecting bubbly water into turbulent boundary layer. Proc. 1994 Cavitation and Gas-Liquid Flow in Fluid Machinery and Devices ASME 190, 185-194. • Kodama, Y., Kakugawa, A., Takahashi, T., and Kawashina, H., 1999, “Experimental Study on Microbubbles and Their Applicability to Ships for Skin Friction Reduction”, 1st Int. Symp. on Turbulent Shear Flow Phenomena, Santa Barbara, U.S.A., pp.1-6. • Liou, William W. Microfluid mechanics. New York: McGraw-Hill, 2005. • Lipton, Douglas W., and Scott Miller. "Recreational Boating in Maryland: An Economic Impact Study, 1993-1994." 6 Mar. 1995. Maryland Marine Trades Conference. • Madavan, N.K., Deutsch, S., Merkle C.L., 1984, “Reduction of Turbulent Skin Friction in Microbuubbles”, Phys. Fluids, Vol. 27, pp.356-363. • McCormick, M.E., Bhattacharyya, R., 1973, “Drag Reduction of a Submersible Hull by Electrolysis”, Naval Engineers Journal, Vol.85, No.2, pp. 11-16. • Pike, John. "Bulbous Bow." Global Security. 7 Oct. 2006. <http://www.globalsecurity.org>. • Scott, Jeff. "Vortex Generators." Aerospaceweb.org | Reference for Aviation, Space, Design, and Engineering. 14 Jan. 2001. <http://www.aerospaceweb.org/question/aerodynamics/q0009.shtml>. • Washington University in St. Louis (2009, March 18). Engineer Devises Ways To Improve Gas Mileage. ScienceDaily • Yoshida, Y., Takahashi, Y., Kato, H., et al. 1998A, “Study on the Mechanism of Resistance Reduction by Means of Micro-Bubble Sheet and on Applicability of the Method to Full-Scale Ship“, 22nd ONR Symp. on Ship Hydrodynamics, pp.1-16.

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