On CFD Simulation of Ski Jumping

Nørstrud, Helge; Øye, Ivar J.

doi:10.1007/978-3-642-04466-3_3

Cited by 10 publications

(2 citation statements)

References 3 publications

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“…CFD can also provide visual or analytical representations of the surrounding flow field. However, the current CFD research on ski jumping is primarily focused on the inrun and flight stages [7][8][9][10][11][12]. The main reason for this is that, compared to the inrun and flight stages, the take-off stage involves rapid and drastic changes in the athlete's posture within a very short period.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation Research on Aerodynamic Characteristics during Take-Off Phase in Ski Jumping

Hu,

Tang,

Liu

2024

Applied Sciences

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In view of the inability to directly and accurately obtain an athlete’s aerodynamic force during the take-off phase through the wind tunnel test, the athlete’s aerodynamic force and surrounding flow field form under different take-off postures are obtained through numerical simulation research, and the effects of different take-off modes on the aerodynamic characteristics during take-off in ski jumping are discussed. The multi-body system composed of the athlete and skis was selected as the research object. By using a partially averaged Navier–Stokes (PANS) turbulence model and a 3D numerical simulation of computational fluid dynamics (CFD), the aerodynamic characteristics of the athlete under different take-off postures were predicted. The take-off modes include the knee-push-hip (KPH) mode and hip-drive-knee (HDK) mode, and the hip joint angle of the HDK mode is significantly greater than that of the KPH mode. First, the aerodynamic force ratio of the athlete’s torso and legs is obviously large. Although the aerodynamic forces of arms themselves are not obvious, they have a great impact on the overall aerodynamic characteristics of the athlete, so the posture of the arms cannot be ignored. The total drag and moment of the HDK mode are significantly higher than that of the KPH mode, and the lift-to-drag ratio of the HDK mode is significantly lower than that of the KPH mode. At first, the total lift of the HDK mode is higher than that of the KPH mode, but in the last attitude, the total lift of the HDK mode does not rise but fall, and finally, the total lift of the HDK mode is lower than that of the KPH mode. The aerodynamic characteristics change dramatically during the take-off phase, and the aerodynamic characteristics of the two take-off modes are quite different, and these changes and differences are difficult to observe during real training and at the competition site. The KPH mode has an obvious aerodynamic advantage over the HDK mode. During the take-off process, the athlete should increase the force generated by the knee joint extension and appropriately reduce the speed of the hip joint extension, control the using force order of the lower limb joints, and push the hip joint extension by the knee joint extension in order to avoid issues, such as the hip joint angle being too large, the hip joint extension angle being too fast, the center of gravity being too far back, and other problems. Studying the aerodynamic characteristics during the take-off phase provides valuable insights for athletes to achieve favorable flight postures after take-off, offering scientific guidance to improve their training strategies and enhance their competitive performance.

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Section: Introductionmentioning

confidence: 99%

Numerical Simulation Research on Aerodynamic Characteristics during Take-Off Phase in Ski Jumping

Hu,

Tang,

Liu

2024

Applied Sciences

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“…CFD has been widely applied in various sports disciplines, including cycling [20], bobsledding [21], and race walking [22]. CFD is considered an important tool for future research on the aerodynamics of ski jumping [1], although current CFD studies in ski jumping mainly focus on the inrun and flight phases [23][24][25][26][27][28][29][30][31]. Gardan et al (2017) employed CFD to investigate the effects of the attack angle and velocity on aerodynamic forces, and their numerical results indicated that velocity had little influence on the lift and drag coefficients during the early flight phase, whereas variations in the attack angle had a significant impact on the lift and drag acting on the athlete [9].…”

Section: Introductionmentioning

confidence: 99%

Computational Fluid Dynamics Simulation Study on Aerodynamic Characteristics under Unfavorable Conditions during Flight Phase in Ski Jumping

Hu,

Tang,

Liu

2024

Applied Sciences

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Objective: The stability of the flight phase in ski jumping is crucial for athletes’ performance and safety. This study aims to investigate the influence of unfavorable conditions on aerodynamic characteristics and flight stability through computational fluid dynamics (CFD) numerical simulations. Methods: The ski jumper and the skis are considered a multi-body system. A detailed three-dimensional (3D) model of this multi-body system under a commonly observed posture during flight is established. The Partially Averaged Navier–Stokes (PANS) turbulence model is employed, and CFD simulations are conducted to predict the aerodynamic characteristics of the multi-body system under lateral environmental wind and asymmetric postures during the flight phase. The conditions of asymmetric postures include yaw rotation and roll rotation. Results: (1) Lateral environmental wind generated a yaw force, yaw moment, and roll moment, which influenced the lift, drag, and pitch moment of the athlete. These forces and moments were relatively small at lower wind speeds (less than 3 m/s) and became more significant at higher wind speeds (greater than 4.5 m/s). (2) Under the influence of yaw rotation or roll rotation, the multi-body system exhibited a noticeable yaw force, yaw moment, and roll moment, all showing a monotonic increasing trend. Moreover, they had a significant impact on the lift, drag, and pitch moment of the multi-body system. Conclusion: (1) The influence of unfavorable conditions was complex, resulting in a significant yaw force, yaw moment, and roll moment on the multi-body system. The adverse effects of roll rotation were generally greater than those of yaw rotation. (2) The multi-body system exhibited self-stabilizing tendencies in yaw and roll. This phenomenon can provide a solution to maintain flight stability by employing appropriate yaw or (and) roll rotation angles, effectively compensating for or even eliminating the adverse effects of lateral environmental wind. (3) Understanding the mechanisms of how unfavorable conditions affect aerodynamic characteristics and stability during flight in ski jumping can provide valuable assistance for real-time prediction and decision making during competitions, as well as scientific guidance for training athletes’ stable flight control and techniques for improving their sport performance.

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Ski Jumping: Aerodynamics and Kinematics of Take-Off and Flight

Virmavirta¹

2018

Handbook of Human Motion

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On CFD Simulation of Ski Jumping

Cited by 10 publications

References 3 publications

Numerical Simulation Research on Aerodynamic Characteristics during Take-Off Phase in Ski Jumping

Numerical Simulation Research on Aerodynamic Characteristics during Take-Off Phase in Ski Jumping

Computational Fluid Dynamics Simulation Study on Aerodynamic Characteristics under Unfavorable Conditions during Flight Phase in Ski Jumping

Ski Jumping: Aerodynamics and Kinematics of Take-Off and Flight

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