基于CFD仿真的跳台滑雪起跳至飞行阶段气动特性关联机制研究

CFD analysis of aerodynamic correlation mechanism in ski jumping takeoff-flight

  • 摘要: 跳台滑雪涉及弹道学与空气动力学,然而现有研究多局限于运动学分析,亟待探索起跳与飞行两阶段间气动特性的内在关联。为此,本文旨在揭示起跳至飞行连续动态过程中运动员/雪板系统的气动特性变化规律,分析起跳与飞行两阶段气动参数同飞行距离的关联性及阶段间参数的相互作用。首先建立具备项目特征的人/板系统精细化模型,并开展计算流体力学仿真,然后,应用相关系数矩阵分析起跳至飞行阶段气动特性指标与飞行距离的关系,以及两阶段间气动特性指标的关系。结果显示,气动力由起跳阻力主导转为飞行升力主导,起跳至飞行过渡期(M5M6)升阻比破1;升力、力矩与飞行距离呈中高度正相关,早期飞行技术执行期(M8M10)最显著,阻力呈负相关;起跳参数与飞行气动特性普遍呈中度至高度正相关。研究表明,离台后身体前倾舒展与雪板V型技术通过增升抑阻实现升阻比“破1”,显著优化气动效能。起跳与飞行的总升力、阻力、力矩呈强关联,证实前期积极或消极的气动效果可传递至后续阶段,同时飞行气动参数可反向评价起跳技术质量。

     

    Abstract: While previous studies have extensively examined how takeoff and flight techniques affect performance (e.g., jump distance) from a kinematic perspective, few have focused on aerodynamic dynamics, nor the intrinsic relationship between these two phases. Using winter field-measured data, this study identifies key moments during the continuous takeoff-to-flight motion to establish dynamic action phases. It aims to: 1) examine variations in aerodynamic characteristics of the athlete-ski system throughout the entire motion, and 2) through correlation analysis, assess how aerodynamic parameters during both takeoff and flight relate to jump distance and interact with each other. A detailed model of the athlete-ski system was developed in 3D modeling software, incorporating event-specific and anthropometric characteristics. CFD simulations were performed using commercial CFD software. The external flow field was simulated with a turbulence model applying symmetry boundary conditions longitudinally. The Reynolds-Averaged Navier-Stokes (RANS) approach modeled complex external flows over moving interfaces. Real-time climate data such as wind force, speed, direction, temperature, humidity, CO2 concentration, and atmospheric pressure near the platform were collected. The study focused on the phase from take-off to stable flight, with ten key kinematic instants (M1M10) representing a continuous dynamic process. The simulations replicated 24 successful long-distance jumps by eight male athletes from national and provincial teams. Pearson correlation analysis examined relationships between aerodynamic parameters and jump distance during take-off (M1M5) and flight (M6M10), and inter-phase connections. The results proved that: 1) The aerodynamic characteristics shifted from drag-dominated during take-off to lift-dominated during the flight phase (M5M10), with both the total and ski lift-to-drag ratios exceeding 1 and increasing markedly, indicating significantly improved aerodynamic efficiency; 2) Jump distance showed strong positive correlations with total lift, body moment, and total moment during the late flight phase (M10), while exhibiting negative correlations with drag throughout most of the take-off and mid-to-late flight phases; 3) Significant associations were observed between the aerodynamic parameters of the take-off (M1M5) and flight (M6M10) phases, with moderate to strong positive correlations between lift, drag, and moment in mid-to-late take-off (M3M5) and mid-to-late flight (M7M10). During the takeoff-to-flight process, the athlete-ski system undergoes a shift from drag-dominated to lift-dominated aerodynamic forces. After leaving the ramp, forward lean and the V-shaped ski technique increase lift while reducing drag, enabling the lift-to-drag ratio to exceed 1 and significantly improving aerodynamic efficiency. Lift and moment positively enhance performance throughout, most notably during stable flight, whereas drag consistently has a suppressive effect. The lift-to-drag ratio plays a key role in stabilizing flight and sustaining glide. Strong correlations were observed between total lift, drag, and moment during takeoff and flight, indicating that positive or negative aerodynamic effects in the takeoff phase propagate into flight. Furthermore, flight aerodynamic parameters can serve as indicators of takeoff technique quality.

     

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