@inproceedings{oai:jaxa.repo.nii.ac.jp:00005482,
 author = {横山, 佳之 and 高見, 圭太 and 田中, 潤一郎 and 宮嵜, 武 and 姫野, 龍太郎 and Yokoyama, Yoshiyuki and Takami, Keita and Tanaka, Junichiro and Miyazaki, Takeshi and Himeno, Ryutaro},
 book = {宇宙航空研究開発機構特別資料: 境界層遷移の解明と制御研究会講演論文集（第41回・第42回）, JAXA Special Publication: Proceedings of the 41st and 42nd JAXA Workshops on Investigation and Control of Boundar-Layer Transition},
 month = {Feb},
 note = {第42回「境界層遷移の解明と制御」研究会（2008年3月31日-4月1日）, Using a high-speed video camera, we measured the trajectory and rotation of a hard baseball thrown by a pitching machine. We determined the drag and lift coefficients of gyro-balls and backspin straight balls, by analyzing the video images. Two kinds of seam pattern, i.e., 2- and 4-seams, relative to the translational direction are investigated for 0.6 x 10(exp 5) < Re < 2.5 x 10(exp 5). The spin parameter (SP) is set to be 0.12, 0.23 and 0.35. The drag coefficient of a 4-seam gyro-ball decreases gradually with Re. In contrast, the drag coefficient of a 2-seam gyro-ball with SP = 0.12 and that with SP = 0.23, decrease in two steps, and their minima (about 0.2) are attained at Re = 2.2 x 10(exp 5) and 1.8 x 10(exp 5), respectively. The drag coefficient of a backspin straight ball with SP = 0.12 and that with SP = 0.23 attain their minima (about 0.3) at Re = 1.5 x 10(exp 5) and 1.35 x 10(exp 5), respectively. The lift coefficient of a backspin straight ball increases monotonically with Re, approaching a constant value 0.2 for Sp = 0.12, 0.25 for SP = 0.23, and 0.3 for SP = 0.35, respectively. No significant difference in the Re-dependence of the drag and lift coefficients is observed between 2- and 4-seams backspin straight balls., 資料番号: AA0064237024, レポート番号: JAXA-SP-08-006},
 publisher = {宇宙航空研究開発機構, Japan Aerospace Exploration Agency (JAXA)},
 title = {硬式野球ボールの空力特性に対する縫目の影響},
 volume = {JAXA-SP-08-006},
 year = {2009}
}