1. Need  In 2050 15% of the Earths carbon dioxide emissions will be from aircrafts (U.S. Global Change Research, 2001)  $61billion has already been spent in aviation for fuel alone (Segelstein, 2008)  If the drag coefficient of a car was reduced by.1 the U.S. oil consumption would decrease by 7.5%. This would save 10 billion gallons of fuel per year. (Fillipone, 1999) Golf Ball Suspension System (GBSS) (Libii, 2005) Purpose The purpose of this experiment is to use golf ball dimpling as a model to improve aerodynamic efficiency. This may be applied to trucks, or airplane propellers and in turn decrease fuel consumption. Hypotheses Field Test  Null Hypothesis H(o)- The golf balls will all travel the same distance and have the same accuracy.  Alternate Hypothesis H(a)- The golf balls with the greatest number of dimples will travel the furthest  Alternate Hypothesis H(a)1- The dimpleless golf ball will be the most accurate. Lab Test  Null Hypothesis H(o)- The golf balls will all have the same drag force.  Alternate Hypothesis H(a)- The drag force will decrease as the numbers of dimples increase.  Alternative Hypothesis H(a)- The dimple characteristics of hexx, smooth, steep, and dimpleless will yield progressively greater drag forces. boojum.as.arizona.edu www.callawaygolf.com/Global/en- GB/Innovation/GolfBallTechnology/ HEXAerodynamics.html http://www.eng.monash.edu.au/uicee/worldtransactions/ WordTransAbstractsVol5No3/23_NjockLibii15.pdf http://pdf.aiaa.org/preview/CDReadyMAAC03_774/PV2003_3662.pdf Drag Coefficients for Conventionally Dimpled, Hexx, and Dimpleless Sphere Bearman and Harvey (1976) Flow Around Smooth SphereFlow Around Dimpled Sphere Libi, 2005- Golf Ball Suspension System Kato, 2005- Steep versus dimpled sphere Bearman and Harvey (1976)- graph representing the drag coefficients of hexx ball, conventional ball, and smooth sphere Smooth Dimples Steep Dimples Smooth vs. Steep Dimples (Kato, 2005) Figure 1- This picture shows the possible dimpling of an airplane propeller. Although just a prototype should dimples be proved to reduce drag, they could greatly decrease fuel consumption. Figure 3Figure 4 Figure 5 Knowledge Base http://www.aviation-history.com/theory/lam-flo Literature Review Figure 6 Figure 7 Figure 8 Figure 6 compares the smooth dimples to steep dimples. Results showed that the flow around the sphere with the smooth dimples created less drag. Figure 7 shows the GBSS inside a wind tunnel. As the wind starts to flow the ball creates an angle with the protractor. In the experiment a dimpled sphere was compared to a smooth sphere. The results showed that the dimpled sphere had a lower drag force. Figure 8- The x-axis shows the initial velocity (m/s) while the y-axis shows the drag coefficient. The results of the experiment showed that at higher speeds the hexx ball has a lower drag coefficient compared to a smooth sphere, and conventionally dimpled sphere. Drag Force=Mass*Graviy*Tan( Figures 3, 4, and 5, all show various spheres and their resulting wakes as they travel through the air. Boundary Layer At low speeds laminar boundary layer is desirable Normally the turbulent boundary layer results in higher drag but the advantage is that airflow is increased and there is more forward momentum. As a result the ball resists the adverse pressure gradient much longer before it separates decreasing drag.