Flight dynamics of an American football in a forward pass
Flight dynamics of an American football in a forward pass
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美式足球向前传球时的飞行动力学
DOI：
10.1007/bf02859892
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发表时间：
2003
影响因子：
1.7
通讯作者：
W. Rae
中科院分区：
文献类型：
--
作者：
W. Rae
本文讨论了美式足球向前传球时的运动。它是用风洞气动力数据对全非线性运动方程进行数值积分，并应用轴对称旋转体大气运动的小角理论进行研究的。数值模拟结果与某些观测到的特征，如范围，飞行时间，自旋和进动频率的比例一致。分析结果揭示了飞行参数对空气动力学的函数依赖性，并深入了解所发生的物理效应。这两种方法都显示了一个在弹道学中被称为“漂移”的特征，即旋转物体的长的、高度拱形的轨迹不位于垂直平面内，而是稍微向左或向右转动，这取决于旋转矢量的方向和空气动力载荷的大小。
The motion of an American football in a forward pass is discussed in this paper. It was investigated by using wind-tunnel aerodynamic data in a numerical integration of the full nonlinear equations of motion, and by application of the small-angle theory for the atmospheric motion of an axisymmetric spinning body. The numerical simulations agree with certain observed features such as the range, flight duration, and ratio of the spin and precession frequencies. The analytic results reveal functional dependences of the flight parameters on the aerodynamics and give insights into the physical effects that occur. Both approaches show a feature that is known as ‘drift’ in the science of ballistics, namely that a long, highly arched trajectory of a spinning body does not lie in a vertical plane, but rather turns slightly to the left or right, depending on the direction of the spin vector and on the magnitudes of the aerodynamic loads.