摘要
足球運動是目前世界最為熱門的項目，足球通常以五邊形與六邊形組成，然而，從2006年世界盃開始，足球的片體以不同的幾何圖形所取代。近年有許多足球研究探討Knuckle effect或Knuckle ball現象，亦稱為「蝴蝶球」現象。本文主要目的是探討足球運動中蝴蝶球的物理現象，以運動生物力學的觀點說明。雷諾數與阻力係數相當重要的參數，當臨界Re的出現，使得球體表面的邊界層形成擾流，讓阻力係數迅速降低，使得阻力降低。現代球體表面粗造化，製造商改變了表面的凹陷、突起、環狀的紋路和片體接縫的長度，讓Cd值迅速降低，使球速能迅速提升。未來研究方向，應朝向如何表現蝴蝶球的技術，使蝴蝶球的策略能成為射門的利器。
並列摘要
Soccer is currently the most popular project in the world. Soccer ball is usually composed of pentagons and hexagons. However, starting from the 2006 World Cup, football tablets have been replaced with different geometric figures. In recent years there have been many studies of football to explore the phenomenon of Knuckle effect or Knuckle ball, also known as the ＂Butterfly Ball＂ phenomenon. The main purpose of this paper is to explore the physical phenomenon of butterfly ball in football, which is illustrated by the viewpoint of sports biomechanics. The parameters of Reynolds number and drag coefficient are very important. When the critical Re occurs, the boundary layer on the surface of the ball forms a turbulent flow, so that the drag coefficient decreases rapidly and the resistance decreases. The surface of the modern soccer ball is roughened, and the manufacturer has changed the length of the surface depressions, protrusions, loop lines, and seams of the sheet body, that the Cd is reducedrapidly, and the ball speed can be rapidly increased. Future research directions should be oriented towards how to represent the technique of the butterfly ball, so that the strategy of the butterfly ball can become a weapon for shooting.