Effect of postural change on characteristics of the fluid during early flight phase in ski jumping

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K01561
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Sports science
• Research Institution: Hokusho University
• Principal Investigator: Yamamoto Keizo 北翔大学, 生涯スポーツ学部, 教授 (00405698)
• Co-Investigator(Kenkyū-buntansha): 坪倉 誠 神戸大学, システム情報学研究科, 教授 (40313366)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: スキージャンプ / バイオメカニクス / 気流可視化 / 数値流体解析 / CFD

Outline of Final Research Achievements

In this study, we aimed to clarify the airflow characteristics of the early flight phase of ski jumping. A 3D CG model of a ski jumper including skis were produced. The time history of joint angles of the body from the approach to the early fight in actual ski jumping was measured, and the CG amination was produced. The fluid characteristics around the jumper were obtained by numerical fluid analysis. The relationship between flight distance and fluid characteristics was investigated for 15 subjects. Based on the flight distance results, they were divided into 3 groups (5 each) and compared. The differences in streamlines around the body and lift-drag ratios were observed among the groups. It was observed that the better the flight distance, the less the airflow separation around the head and the back, and the higher the lift-drag ratio in the approach posture.

Free Research Field

スポーツ・バイオメカニクス

Academic Significance and Societal Importance of the Research Achievements

本研究成果の学術的意義は，ダイナミックな姿勢変化を伴う身体運動を対象に，連続的な流体解析のフレームワークを構築したことである．高速滑降，飛行するスキージャンプの研究において，流体解析は不可欠なテーマであるが，これを移動境界問題として取り扱った研究は過去にはない．本研究で構築したフレームワークは，２次元動作分析から得られる関節角度から３次元アニメーションを制作し，不可視の流体情報を短時間に可視化できるため，指導や競技の現場で活用できる．その社会的意義は大きい．今後，体型やジャンプスタイルによって，最適動作の提案や，スーツやヘルメット等の用具開発にも有効活用が期待できる．