A Parametric Analysis of the Aerodynamic Characteristics of Volleyballs in Turbulent Flow Hans J. Thomas a Thesis Submitted in P
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A Parametric Analysis of the Aerodynamic Characteristics of Volleyballs in Turbulent Flow Hans J. Thomas A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Aeronautics and Astronautics University of Washington 2012 Robert Breidenthal, Chair James Riley Program Authorized to Offer Degree: Aeronautics and Astronautics University of Washington Abstract A Parametric Analysis of the Aerodynamic Characteristics of Volleyballs in Turbulent Flow Hans J. Thomas Chair of Supervisory Committee: Professor Robert E. Breidenthal Aeronautics and Astronautics A wind tunnel experiment was conducted to compare the flight path characteristics and drag of current models of volleyballs. An open circuit low speed wind tunnel was primarily used to gather lift and drag data on multiple models of volleyballs in super-critical Reynolds number flows. The models tested were the Baden VX5E-01, Baden VX450C-230, Baden VX450-02, Mikasa MVA200, and Molten V5M5000. Analysis was conducted to determine the relationship between cavity dimensions on the balls and the lift and drag characteristics of the balls. Conditions were based on indoor volleyball conditions set by the International Federation of Volleyball (FIVB) with Reynolds numbers ranging from 2x10 5 to 4.3x10 5. Recommendations were provided for future designs of volleyballs to improve aerodynamic performance. TABLE OF CONTENTS List of Figures ............................................................................................................................................... ii List of Tables ............................................................................................................................................... iii Nomenclature ............................................................................................................................................... iv Chapter 1: Introduction ................................................................................................................................. 1 Chapter 2: Experimental Procedure .............................................................................................................. 3 2.1 Constraints .......................................................................................................................................... 3 2.2 Wind Tunnel Testing .......................................................................................................................... 3 2.3 Data Processing ................................................................................................................................... 5 2.4 Measurements ..................................................................................................................................... 7 Chapter 3: Results ......................................................................................................................................... 9 3.1 Evolution of a Volleyball .................................................................................................................... 9 3.2 Comparing New Models ................................................................................................................... 14 3.3 Adjusting Skiving ............................................................................................................................. 17 3.4 Cavity Flows and Momentum Thickness .......................................................................................... 19 Chapter 4: Conclusion ................................................................................................................................. 25 4.1 Discussion Analysis .......................................................................................................................... 25 4.2 Recommendations for Future Designs .............................................................................................. 26 4.3 Improvements for Future Work ........................................................................................................ 26 Bibliography ............................................................................................................................................... 29 Appendix A : Labview ................................................................................................................................ 30 Appendix B : MATLAB Code .................................................................................................................... 30 Appendix C : Configuration Images ........................................................................................................... 30 Appendix D : Texture Images ..................................................................................................................... 31 Appendix E : Seam Images ......................................................................................................................... 32 LIST OF FIGURES Figure 1: Testing Apparatus. ......................................................................................................................... 4 Figure 2: Diagram of Total Lift .................................................................................................................... 6 Figure 3: Baden Volleyballs ......................................................................................................................... 9 Figure 4: Baden Balls at Different Configurations ..................................................................................... 11 Figure 5: Kirsten Tunnel Drag Performance ............................................................................................... 12 Figure 6: Kirsten Tunnel Lift Performance ................................................................................................. 12 Figure 7: Drag Crisis for a Sphere .............................................................................................................. 14 Figure 8: Mikasa and Molten Volleyballs ................................................................................................... 14 Figure 9: Drag Performance for All Models ............................................................................................... 16 Figure 10: Lift Performance for All Models. .............................................................................................. 16 Figure 11: Drag Performance with Changing Skiving ................................................................................ 18 Figure 12: Lift Performance with Changing Skiving .................................................................................. 18 Figure 13: Drag Performance Related to z .................................................................................................. 21 Figure 14: Correlation Between Drag and z ............................................................................................... 23 Figure 15: Lift Performance Related to y ................................................................................................... 24 Figure 16: Baden Original Texture ............................................................................................................. 31 Figure 17: Baden Lexum Texture ............................................................................................................... 31 Figure 18: Baden Dimple Texture .............................................................................................................. 31 Figure 19: Mikasa Texture .......................................................................................................................... 31 Figure 20: Molten Texture .......................................................................................................................... 31 Figure 21: Baden Original Seam ................................................................................................................. 32 Figure 22: Baden Lexum Seam ................................................................................................................... 32 Figure 23: Baden Dimple Seam .................................................................................................................. 32 Figure 24: Mikasa Seam ............................................................................................................................. 32 Figure 25: Molten Seam .............................................................................................................................. 32 Figure 26: Baden Min Skiv Seam ............................................................................................................... 32 Figure 27: Baden No Skiv ........................................................................................................................... 32 ii LIST OF TABLES Table 1: Seam Dimensions ......................................................................................................................... 10 Table 2: Dimple Dimensions ...................................................................................................................... 15 Table 3: Ball Quantity and Depth Quality Factors ..................................................................................... 20 Table 4: Momentum Thickness at Various Speeds ..................................................................................... 20 Table