ヤリの最適投げ出し条件と穂先の効果

抄録

Throwing the javelin is a field event in athletics. There are specific regulations to which the javelin must conform. In this study, optimization of the flight distance was carried out using a genetic algorithm. Tips with three different shapes were designed within the rules. One design was that of a typical commercially available tip. The second design was thinner and the third design thicker than the commercially available tip. The aerodynamic forces acting on the three types of javelin with respect to the angle of attack (AoA) were calculated using a commercial solver. In this optimization study, the design variables were the initial conditions determined by the thrower, and the objective function was the flight distance. The flight distances were estimated by numerical integration of the equations of motion. It was found that the flight distance for the thinner design was shorter than that for the other two types. The key for longer flight distances is that the drag should be small (AoA should be kept small) in the first half of the flight, and that the lift should be large (AoA should be large) in the second half of the flight.