Trajectories of launched spherical aerial shells were recorded with the high-speed video camera and rotations of the shells were confirmed in our experiments. Based on the experimental results, it can be understood that rotation and direction of rotational axis of a launched spherical aerial shell are a random phenomenon by various influence factors. Moreover, attenuation of the rotating speed of a shell by the viscosity of air was observed and torque coefficient was obtained by the experiments. With these experimental results, the three-dimensional equations of motion which took in Magnus force and rotational attenuation were calculated numerically, and it was examined how much Magnus force would have affected movement of a launched rotating spherical aerial shell.istent with the literature value.
本研究は打上げ煙火玉の運動を高速度ビデオカメラで撮影し，煙火玉の回転の有無と回転軸の方向を確認した。実験結果によって，煙火玉の回転・無回転および回転軸の方向が種々の影響因子によるランダム現象であることがわかった。また，空気の粘性による煙火玉の回転速度の減衰を実験により調べた。これらの実験結果に基づいて，Magnus力および煙火玉の回転減衰方程式を取り入れた3次元モデルを数値的に計算し，Magnus力が煙火玉の運動にどの程度の影響を与えているかを検討した。
Magnus force, Rotating sphere, Spherical aerial shell, Fireworks, Numerical calculation