Fluid Mechanics of Cricket and Tennis Balls

COFFEE_KLATCH · Invited

Abstract

Aerodynamics plays a prominent role in defining the flight of a ball that is struck or thrown through the air in almost all ball sports. The main interest is in the fact that the ball can often deviate from its initial straight path, resulting in a curved, or sometimes an unpredictable, flight path. It is particularly fascinating that that not all the parameters that affect the flight of a ball are always under human influence. Lateral deflection in flight, commonly known as swing, swerve or curve, is well recognized in cricket and tennis. In tennis, the lateral deflection is produced by spinning the ball about an axis perpendicular to the line of flight, which gives rise to what is commonly known as the \textit{Magnus effect.} It is now well recognized that the aerodynamics of sports balls are strongly dependent on the detailed development and behavior of the boundary layer on the ball's surface. A side force, which makes a ball curve through the air, can also be generated in the absence of the Magnus effect. In one of the cricket deliveries, the ball is released with the seam angled, which trips the laminar boundary layer into a turbulent state on that side. The turbulent boundary layer separates relatively late compared to the laminar layer on the other side, thereby creating a pressure difference and hence side force. The fluid mechanics of a cricket ball become very interesting at the higher Reynolds numbers and this will be discussed in detail. Of all the round sports balls, a tennis ball has the highest drag coefficient. This will be explained in terms of the contribution of the ``fuzz" drag and how that changes with Reynolds number and ball surface wear. It is particularly fascinating that, purely through historical accidents, small disturbances on the ball surface, such as the stitching on cricket balls and the felt cover on tennis balls are all about the right size to affect boundary layer transition and development in the Reynolds numbers of interest. The fluid mechanics of cricket and tennis balls will be discussed in detail with the help of latest test data, analyses and video clips.

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Authors

  • Ivan Marusic

    Department of Organismic and Evolutionary Biology, Harvard University, School of Engineering and Applied Sciences, Harvard University, Georgia Institute of Technology, Nanyang Technological University, University of Minnesota, Kyoto University, Universit\`a degli Studi di Trieste, Eindhoven University of Technology, University of Washington, Fachbereich Physik, Philipps-Universit\"at Marburg, Germany, Department of Science and Technology, University of Twente, The Netherlands, Department of Physics, The Chinese University of Hong Kong, Hong Kong, Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong, China, University of Malaga (Spain), Virginia Polytechnic Institute and State University, Experimental and Computational Laboratory for the Analysis of Turbulence (ECLAT), King's College London, Strand, London WC2R 2LS, UK, Hokkaido University, Texas A&M University, California Institute of Technology, United Technologies Research Center, Center for Turbulence Research, Stanford University, Stanford, CA 94305, Georgia Tech, Imperial College, Stevens Institute of Technology, Duke University, Orbital Technologies Corporation, University College London, Oxford University, University College London (UCL), Cornell University, Yale University, PUC-Rio, Laboratoire Mati\`ere et Syst\` emes Complexes, UMR 7057 CNRS \& Un iversit\'e Paris Diderot, Paris, France, Laboratoire Physico-chimie des Polym\`eres et Milieux Dispers\'es, UMR 7615 CNRS, ESPCI, Paris, France, University of Illinois at Chicago, Harvard Medical School, INRIA Rocquencourt, Illinois Institute of Technology, Purdue University, Defence Science and Technology Organisation, Stanford University, University of Melbourne, Poznan University of Technology, Northeastern University, Berlin Institute of Technology, University of Colorado, University of California, Santa Barbara, University of California, Berkeley, National Institute for Aquatic Resources, Technical University of Denmark, Department of Physics and Center for Fluid Dynamics, Technical University of Denmark, Brown University, University of Connecticut Health Center, Univ. of Texas at Austin, University of Cambridge, Technische Universitaet Darmstadt, Darmstadt, Germany, Iowa State University, NYU, Dept Phys, Ctr Soft Matter Res, New York, NY 10003 USA, Aix Marseille Univ U1, IUSTI, CNRS, UMR Polytech Marseille 6595, F-13453 Marseille 13, France, DAMTP, University of Cambridge, Russian Academy of Sciences, Irkutsk, Technion, Faculty of Aerospace Engineering, Seattle University, DIAS, University of Naples Federico II, Orsay Maths Department, CNRS, Paris-Sud 11 University (France), Ecole Polytechnique, Kangnung National University, NJIT, Los Alamos National Laboratory, UNC Charlotte, University of Maryland, NASA-JPL, MIT, University of Wisconsin-Madison, University of Mississippi, University of Michigan, Tennessee Technological University, Carnegie Mellon University, Benjamin Levich Institute, University of Texas at Austin, University of Delaware, Purdue University, West Lafayette, The University of Western Australia, Virginia Tech, University of South Carolina, University of Twente, National Cheng Kung University, University of Michigan - Department of Biomedical-Engineering, Kuwait University, Clarkson University, Bucknell University, Center for Turbulence Research, Stanford University, Department of the Mechanical Engneeing, Shizuoka University, University of California, San Diego, Princeton University, Harvard Medical School, Harvard University, Seoul National University, University of Notre Dame, University of New Hampshire, Olin College, Brigham Young University, RWTH Aachen, Department of Physics, IREAP and IPST, University of Maryland, Department of Physics and IREAP, University of Maryland, University of Maryland College Park, School of Mathematics, University of Bristol, University Walk, Bristol BS8 1TW, Technische Physik, Universitaet des Saarlandes, 66041 Saarbruecken, Rensselaer Polytechnic Institute, Southern Methodist University, University of Arizona, TU Darmstadt (Germany), TU Darsmtadt (Germany), Harvey Mudd College, University of Nottingham, University of Sevilla, University of Malaga, Imperial College London, University of Illinois at Urbana-Champaign, George Washington University, Johns Hopkins University, Syracuse University, U. S. Army ARDEC, LANL, University of Utah, Politechnica Madrid, The City College of the City University of New York, U of Wisconsin River Fall, Nagoya Institute of Technology, Japan, Massachusetts Institute of Technology, Harvard University, University of Maryland, College Park, St. Anthony Falls Laboratory, University of Minnesota, The State University of New York at Buffalo, University of Buffalo, SUNY, Department of Materials Science and Engineering University of Tennessee, Knoxville, TN, Department of Mathematics, New Jersey Institute of Technology, Newark, NJ, Instituto de F\'isica Arroyo Seco, Universidad Nacional del Centro de la Provincia de Buenos Aires, Pinto 399, 7000, Tandil, Argentina, The University of New Mexico, Division of Mechanical and Space Engineering, Hokkaido University, Department of Mechanical Engineering, Osaka University, Sandia National Laboratories, Binghamton University, UCSB, UC San Diego, Laocharoensuk, Arizona State University, Ben-Gurion University of the Negev, Institut fuer Theoretische Physik I, Ruhr-Universitaet Bochum, NASA Langley Research Center, United States Naval Academy, University of California, Los Angeles, CNRS, University of Massachusetts Amherst, ESPCI and Ecole polytechnique, Paris, France, Lyderic Bocquet, Université de Lyon, City College of New York, Wesleyan University, Lehigh University, Kyushu Institute of Technology, IMFT, Universite de Toulouse, France, Pennsylvania State University, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia, Department of Mechanical Engineering, National University of Singapore, Stony Brook University, Petroleum Institute, Department of Mechanics and Aeronautics,University of Rome ``La Sapienza'', Linne Flow Centre, KTH Mechanics, Stockholm, Department of Physics, Michigan Technological University, Department of Mechanical Engineering. University of Washington, The University of Tokyo, The Johns Hopkins University, Purdue University, West Lafayette, IN 47909, Physics of Fluids, University of Twente, The Netherlands, School of Engineering and Applied Sciences, Harvard University, Cambridge, USA, McGill University, Univ. Calif. at Davis, University of Louisville, University of Puerto Rico at Mayaguez, Tokyo Institute of Technology, Laboratoire J.-A. Dieudonne, Universite de Nice Sophia Antipolis, France, Dipartimento di Fisica Generale, Universit\`a di Torino, Italy, Institut Pasteur, Paris, France, ICTP, Auburn University, Northwestern University, University Magdeburg, St. Anthony Falls Laboratoy, Department of Civil Engineering, University of Minnesota, Department of Mechanical Engineering, University of Minnesota, International Centre for Theoretical Physics - University of Maryland, University of Maryland and Texas A\&M, International Centre for Theoretical Physics, NTNU, St. Anthony Falls Lab, University of Minnesota, Escuela T\'ecnica Superior de Ingenieros Aeron\'auticos, UPM (Madrid, Spain), Department of Physics, Ochanomizu University, Samsung Engineering Co. Ltd., Harvard Univ., Penn. State Univ., A*STAR Institute of High Performance Computing, Rutgers University, RWTH Aachen University, Xi'an Jiaotong University, Okayama University, Osaka University, London, UK, Manchester, UK, FLAIR, Dept of Mechanical and Aerospace Engineering, Monash University, Australia, Manchester Interdisciplinary Biocentre, University of Manchester, Manchester, M1 7DN, UK, University of Colorado at Boulder, Oregon State University, UCL, Queen's University Canada, Delft University of Technology, DLR Goettingen, Scripps Institution of Oceanography, University of California, San Diego, Sports Aerodynamics Consultant, Mountain View, California, Mechanical Engineering, Johns Hopkins University, New Mexico State University, Clark University, University of North Carolina at Charlotte, Earth and Planetary Science, University of California - Berkeley, St. Anthony Falls Laboratory, Civil Engineering, University of Minnesota, Florida Atlantic University, JHU/APL, Université Catholique de Louvain, Belgium, Monash University, Ritsumeikan University, Japan, Michigan State University, ANL, Ship Scientific Research Center of China, Wuxi, 214082, Department of Mechanical Engineering, University of South Carolina, Columbia, SC, USA, University of Toronto, Konkuk University, Seoul, Korea, Seoul National University, Seoul, Korea, NASA Glenn Research Center, Royal Military College of Canada, University of Vermont, Mechanical and Aerospace Engineering, Cornell University, Leibniz Institute for Tropospheric Research, NCAR, CNRM; CNRS-GAME, Universit\'e de Toulouse, IMFT, University of British Columbia, Institut Jean le Rond D'Alembert, UMR 7190, Universit\'e Pierre et Marie Curie, Paris, Imperial College London, UK, KTH Mechanics, Stockholm, Sweden, University of Montenegro, Universidad Nacional Autonoma de Mexico, James Franck Institute, University of Chicago, Institute of Applied Mechanics, National Taiwan University, Clemson University, Colorado State University, The University of North Carolina, Chapel Hill, Dynaflow, Inc., University of Wisconsin, PMMH, ESPCI / LadHyx, Polytechnique, Insitutec, New York University, Dept. of Plant and Microbial Biology, U.C. Berkeley, Department of Organismal Biology, Harvard University, Department of Mathematics, University of California, Berkeley, Caltech, The Ohio State University, University of Southampton UK, Queen's University, Kingston, Canada, University of Illinois