Aerodynamic force data for a V-style ski jumping flight

Seo, Kazuya; Watanabe, Isao; Murakami, Masahide

doi:10.1007/bf02843971

Cited by 43 publications

(35 citation statements)

References 2 publications

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“…The virtual ski jumper had a mass, including equipment, of 70 kg and a height of 1.76 m [10], and used commercially available skis of 2.57 m length (146% of athlete's height), 11.5 cm width, and ski bindings (boot tip to ski tip distance of 57% of ski length). The equipment complied with Fe´de´ration Internationale de Ski [17] specifications.…”

Section: Hypothetical Ski Jumper and Competition Conditionsmentioning

confidence: 99%

“…The forward leaning angle (y) was sampled from 0 to 401 at 101 intervals. Hip angle (b) was held at 01 (based on the wind tunnel database of Seo et al [10]), and the arm abduction angle was constant at 101 (arms held to the sides of the body). Simulation of competition levels incorporated freestream air velocities (V a ) of 20 m/s (typical at takeoff in medium jumping hills), 25 m/s (large hills) and 30 m/s (ski flying hills) [15][16][17].…”

Section: Hypothetical Ski Jumper and Competition Conditionsmentioning

confidence: 99%

“…Very few studies [e.g. 10,13] have examined oscillatory pitching motion. Uppermost, the mechanisms of static stability in pitch in ski jumping have not been explicated.…”

Section: Introductionmentioning

confidence: 99%

“…Lateral motion depends on cross-coupling of roll and yaw [7]; however, longitudinal stability can be assessed independently. We might expect to find different postural configurations of the ski jumper that vary in terms of aerodynamic efficiency [8,9] and longitudinal stability [10].…”

Section: Introductionmentioning

confidence: 99%

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Mechanics of flight in ski jumping: aerodynamic stability in pitch

Marques-Bruna

Grimshaw

2009

Sports Technol.

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This study examines aerodynamic stability in pitch in ski jumping. Static stability implies automatic return to trimmed flight after a sudden disturbance and dynamic stability involves gradual damping of oscillatory motion. Both have implications for flight control and safety. A 3-D inertia model of a ski jumper and the Planica K185 jumping hill profile were constructed using computer-aided design. Inertia, jump performance, and aerodynamic efficiency and stability parameters were computed for variations in V-style posture using mathematical modeling. Pitching moment at a 01 angle of attack was positive, and the condition dM/dao0 at equilibrium was satisfied, indicating that the athlete is inherently stable. Enhanced flight posture consists of a ski-opening angle of 301 and a forwardleaning angle of 101. This is a high-lift configuration with a large static margin that triggers a steep dM/da slope and high oscillatory frequency upon deviations from trimmed attitude. Mechanisms of stability in pitch are proposed, founded upon theoretical aerodynamics. r

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Section: Hypothetical Ski Jumper and Competition Conditionsmentioning

confidence: 99%

Section: Hypothetical Ski Jumper and Competition Conditionsmentioning

confidence: 99%

“…Very few studies [e.g. 10,13] have examined oscillatory pitching motion. Uppermost, the mechanisms of static stability in pitch in ski jumping have not been explicated.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Mechanics of flight in ski jumping: aerodynamic stability in pitch

Marques-Bruna

Grimshaw

2009

Sports Technol.

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“…Seo et al 15) performed a wind tunnel test for the full-size model to analyze the aerodynamic characteristics of the ski jumper model during flight under aerodynamic stall. In the case of a high angle of attack, the lift force is highly increased during flight using the V-style compared with that of using the parallel style.…”

Section: Introductionmentioning

confidence: 99%

Aerodynamic Analysis on Postures of Ski Jumpers during Flight using Computational Fluid Dynamics

Ryu

Cho

2015

Trans. Japan Soc. Aero. S Sci.

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The aerodynamic characteristics of a ski jumper model in various postures are analyzed using a commercial computational fluid dynamics tool. The purpose of this study is to understand the aerodynamic characteristics of ski jumping. The range of flying postures for ski jumpers is determined as widely as possible to simulate the optimal flight position of ski jumpers. The computational results are in good agreement with experimental results. The aerodynamic characteristics are influenced by the hip and body angles of the ski jumper model during the flight. The lift-to-drag ratio of ski jumpers is increased as hip angle increases. However, as the hip angle increases, the region of the angle of attack becomes restricted for stable flight. The augmentation of the body angle can enhance the most favorable angle of attack, because the body angle is likely to result in a cambered airfoil. In conclusion, the ski jumper should maintain a high hip angle with an angle of attack that stabilizes the flight condition, to improve flight distance.

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Mechanics of flight in ski jumping: aerodynamic stability in roll and yaw

Marques-Bruna¹,

Grimshaw

2009

Sports Technol.

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This study identifies the mechanisms of static and dynamic, lateral and directional aerodynamic stability in ski jumping based upon theoretical principles of aerodynamics and aeronautics. Static stability for systematic variations in flight posture was simulated utilizing an inertia model of the ski jumper generated using computer-aided design and mathematical modeling. Theory suggests that differential ski velocity and asymmetric angle of attack provide aerodynamic damping during a roll. Ski dihedral and lateral centre-of-pressure migration produce a restorative dihedral effect. However, forward sweep, body-ski interaction and ski side drag are destabilizing in roll. Differential ski tangential velocity provides aerodynamic damping during yawing motion; however, forward sweep, slender-body flow and body-ski interaction are destabilizing in yaw. Only the ski-shielding effect contributes to static yaw stability. Rolling and yawing motion impinge upon one another. Aerodynamic damping of dynamic Dutch roll oscillation is only light, however inertial damping of dynamic oscillation is heavy in ski jumping. The simulation data suggest that a flight posture of a ski opening angle of 301 and forward leaning angle of 101 enhances inertial damping and aerodynamic stability at any competition level. This theoretical analysis lays the foundations for the wind tunnel-based study of integrated flight stability, where it is imperative to determine the influence of real viscous effects upon flight stability. The present analysis has also applications for enhanced safety in ski jumping. r

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Aerodynamic force data for a V-style ski jumping flight

Cited by 43 publications

References 2 publications

Mechanics of flight in ski jumping: aerodynamic stability in pitch

Mechanics of flight in ski jumping: aerodynamic stability in pitch

Aerodynamic Analysis on Postures of Ski Jumpers during Flight using Computational Fluid Dynamics

Mechanics of flight in ski jumping: aerodynamic stability in roll and yaw

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