关于男子低重心标枪出手条件的分析

An Analysis of Release Conditions for Men's Javelin with Low Center of Gravity

在标枪风洞测力实验基础上,建立标枪飞行数理模型进行计算机优化,得到了有规律的结论,结合投掷实践分析了标枪出手适宜条件。出手初速在25m/s～30m/s的范围内,最佳出手条件是:投掷角为40°,迎角为-11°。就投掷成绩而言,负攻角比零攻角好,零攻角又比正攻角好。低重心标枪俯仰力矩值比旧标枪大,低重心标枪出手条件不好,投掷成绩下降幅度比旧标枪大。一般情况下投掷角不能小,攻角绝对值不能大,这样相应成绩更好些。投掷标枪不能沿纵轴用力,也不可能沿纵轴用力。标枪以不为零的攻角出手是获得空气动力效率的充分必要条件。

Based on the experiments done in wind tunnel on javelin,the author established a mathematical model of javelin flying with computer optimization and obtained the results with laws. The proper conditions of javelin release were also analysed. With the initial velocity of throwing within 25-30m/s,the optimum conditions of releasing javelin are: the optimum angle of projection is 40°,the angle of attack is-11°. As far the effect of throwing javelin,better performance will be achieved with a minus angle of attack than with zero angle of attack, while the latter will result in longer distance than a plus angle of attack. In case of poor conditions, the performance with low center of gravity javelin will be worse than that with the old model javelin. In general,the angle of throwing should not be small,and the absolute value of angle of attack should not be large, so that longer distance of throwing coule be obtained. Releasing force should not be applied along with the axis of javelin. The angle of attk should not be equal to zero,in order to obtain aerodynamic effects.