The Effect of Micro Bubbles and Bulbous Bow on the Aerodynamic

Efficiency of a BoatHarry Kucharczyk

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

Knowledge BaseBulbous Bow o Reduces shock wave

oDecrease in friction drag

http://www.globalsecurity.org

www.marinefirefighting.com

Knowledge BaseMicro Bubbles

•Inserted in the boundary layer

•Decreased viscosity and density of the fluid

www.impactlab.com

Literature ReviewMcCormick 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

Engineering GoalsExamine the effects of passive and active flow

in boat drag reduction

PurposeReduce skin friction drag by using methods

of passive and active flow control

Boat with Bulbous Bow n=2

Measure mass and acceleration to calculate the force

Analyze data using SPSS One Way ANOVA and a Scheffe post Hoc test.

Insert Microbubbles in the Boundary Layer using a porous plate (200-400 micrometers)

Normal Boat n=2

Experimental Setup

Porous Plate

Bulbous Bow

Newton’s Second Law

Force = Acceleration X Mass

Force = Mass X (Velocity1 – Velocity2) (Time1 – Time2)

Do AbilityWater Tunnel is accessible in the lab Boat has already been constructedBulbous bow can easily be inserted into the

boatMicrobubbles can be made through simple

appliances

BudgetItem Vendor Category # Size QuantityPrice

Water Tunnel Lab

Boat Lab

Porous Plates

ICT Internationa

l0604D04-

B15M15in

radius 5

Micro Acquarium Bubbler Rena 17163057048 2in 1 $4.44

Air Injector Lab

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.