The effect of shape on the aerodynamic and thermal performance of hypersonic projectiles launched by a ground-based railgun

Hirotaka Kasahara, Akiko Matsuo

研究成果: Conference contribution

1 被引用数 (Scopus)


In this paper, the effect of hypersonic-projectile design upon its aerodynamic coefficient is investigated to optimize projectile shape for ground-based-railgun launch. Previous studies on railgun-launch systems have suggested that projectiles experience significant thermal and aerodynamic effects when exiting the launcher because of their hypersonic exit velocity and the high enthalpy flow in the standard atmospheric condition. When designing a hypersonic projectile, the aerodynamic coefficient and thermal protection are crucial for maximizing range and withstanding heat. Two conditions of hypersonic flight, such as free flight and transitional ballistics, are simulated herein. To investigate the projectile’s geometric effect in the steady-flight condition, projectiles designed based on theory and empirical observation are compared. The aerodynamic result suggests that sharper projectiles do not always have smaller drag coefficients in simulation and theory because of a tradeoff between maximum pressure at the tip and pressure distribution on the latter half of the front shape. While temperature shows a similar trend compared to pressure, the maximum-temperature point is affected by projectile bluntness. Therefore, to optimize hypersonic design for thermal effect, it is inappropriate to adopt excess thermal protection at the tip, and an accurate prediction of maximum-heat-flux point is important. In addition to free-flight simulation, a transitional-ballistics simulation is performed. The interior and transitional calculations indicate that the precursor shockwave and sabot affect the flow field around the projectile. The sabot-separation phase can be divided into four stages based on the characteristics of the flow field. In the first and second stages, before the projectile undergoes the precursor shockwave, its shape has little effect on drag or velocity. However, when the projectile interacts with the sabot in the third and fourth stages, geometric effects can be observed. The theoretically optimized projectile is found to keep the highest flight velocity from transitional ballistics to free-flight.

ホスト出版物のタイトルAIAA Aerospace Sciences Meeting
出版社American Institute of Aeronautics and Astronautics Inc, AIAA
出版ステータスPublished - 2018
イベントAIAA Aerospace Sciences Meeting, 2018 - Kissimmee, United States
継続期間: 2018 1月 82018 1月 12


名前AIAA Aerospace Sciences Meeting, 2018


ConferenceAIAA Aerospace Sciences Meeting, 2018
国/地域United States

ASJC Scopus subject areas

  • 航空宇宙工学


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