1.China Institute of Sport Science;2.School of Kinesiology,Shanghai University of Sport
目的 探讨运动员姿态(包括上半身弯曲角度以及身体与滑雪板夹角)对跳台滑雪空中飞行气动特性的影响。方法 将跳台滑雪运动员与滑雪板作为一个多体系统,采用部分时均(partially averaged Navier-Stokes,PANS)湍流模型并通过计算流体力学(computational fluid dynamics,CFD)方法数值模拟预测了不同运动员姿态下跳台滑雪空中飞行空气动力学特性。上半身弯曲角度计算工况包括10°、14°、18°、22°和26°,身体与滑雪板夹角计算工况包括8°、12°、16°、20°和24°。结果 1)受上半身弯曲角度增大变化的影响,多体系统、运动员以及滑雪板的升力、阻力,滑雪板的俯仰力矩数值均呈现单调递减趋势,但总升阻比先增大后减小；多体系统的俯仰力矩数值先减小后增大；运动员的俯仰力矩数值先微幅增大后减小。2)受身体与滑雪板夹角增大变化的影响,多体系统以及滑雪板的升力、阻力均先增大后减小再增大,但总升阻比先减小后增大再减小；运动员的升力、阻力以及俯仰力矩均呈现单调递增趋势；多体系统以及滑雪板的俯仰力矩数值均先增大后减小。结论 1)上半身弯曲角度以及身体与滑雪板夹角均对跳台滑雪空中飞行气动特性产生一定的影响,相较而言,上半身弯曲角度的影响普遍显著于身体与滑雪板夹角的影响。2)从寻求相对最优总升阻比以及空中飞行稳定性的角度出发,上半身弯曲角度的优选范围为14°~18°,身体与滑雪板夹角的优选范围为16°~20°。3)运动员姿态(包括上半身弯曲角度以及身体与滑雪板夹角)对跳台滑雪空中飞行气动特性的影响机理能够为比赛预判与决策提供有效的辅助支持,也为运动员空中飞行稳定性控制与技术训练提供科学指导。
Objective To determine the effects of athlete's posture on the aerodynamic characteristics during flight in ski jumping, including bending angle of upper body and angle between body and skis. Methods The athlete and skis were regarded as a multi-body system. By using partially averaged Navier-Stokes (PANS) turbulence model and numerical simulation of computational fluid dynamics (CFD), the aerodynamic characteristics during flight under different athlete's postures were predicted. The calculation conditions of bending angle of upper body include 10°, 14°, 18°, 22° and 26°, and the calculation conditions of angle between body and skis include 8°, 12°, 16°, 20° and 24°. Results 1) As the bending angle of upper body increases, the lift and drag of the multi-body system, the athlete and skis, and the pitch moment of skis all show a monotonously decreasing trend., but the total ratio of lift and drag increases first and then decreases. Meanwhile, the pitch moment value of the multi-body system decreases first and then increases, and the pitch moment value of athlete increases slightly and then decreases. 2) As the angle between body and skis increases, the lift and drag of the multi-body system and skis increase first, then decrease and then increase, but the total ratio of lift and drag decreases first, then increases and then decreases.. Meanwhile, the lift, drag and pitching moment of the athlete increase monotonously, and the values of the pitching moment of the multi-body system and the skis increase first and then decrease. Conclusions 1) The bending angle of upper body and the angle between body and skis have a certain influence on the aerodynamic characteristics during flight in ski jumping. In contrast, the effect of bending angle of upper body is generally significantly higher than that of angle between body and skis. 2) From the point of view of finding the relative optimal total lift-resistance ratio and flight stability, the optimal range of bending angle of upper body is 14°~18°, and the optimal range of angle between body and skis is 16°~20°. 3) The influence mechanism of bending angle of upper body and angle between body and skis on the aerodynamic characteristics during flight in ski jumping can provide effective auxiliary support for on-the-spot prediction and decision-making, and also provide scientific guidance for flight stability control and technical training for athletes.