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

Hirotaka Kasahara, Akiko Matsuo

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

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.

Original languageEnglish
Title of host publicationAIAA Aerospace Sciences Meeting
PublisherAmerican Institute of Aeronautics and Astronautics Inc, AIAA
Edition210059
ISBN (Print)9781624105241
DOIs
Publication statusPublished - 2018 Jan 1
EventAIAA Aerospace Sciences Meeting, 2018 - Kissimmee, United States
Duration: 2018 Jan 82018 Jan 12

Other

OtherAIAA Aerospace Sciences Meeting, 2018
CountryUnited States
CityKissimmee
Period18/1/818/1/12

Fingerprint

Rail guns
Hypersonic aerodynamics
Projectiles
Aerodynamics
Free flight
Ballistics
Hot Temperature
Flow fields
Catapults (aircraft launchers)
Drag coefficient
Pressure distribution
Phase separation
Thermal effects
Drag
Heat flux
Enthalpy

ASJC Scopus subject areas

  • Aerospace Engineering

Cite this

Kasahara, H., & Matsuo, A. (2018). The effect of shape on the aerodynamic and thermal performance of hypersonic projectiles launched by a ground-based railgun. In AIAA Aerospace Sciences Meeting (210059 ed.). American Institute of Aeronautics and Astronautics Inc, AIAA. https://doi.org/10.2514/6.2018-0048

The effect of shape on the aerodynamic and thermal performance of hypersonic projectiles launched by a ground-based railgun. / Kasahara, Hirotaka; Matsuo, Akiko.

AIAA Aerospace Sciences Meeting. 210059. ed. American Institute of Aeronautics and Astronautics Inc, AIAA, 2018.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Kasahara, H & Matsuo, A 2018, The effect of shape on the aerodynamic and thermal performance of hypersonic projectiles launched by a ground-based railgun. in AIAA Aerospace Sciences Meeting. 210059 edn, American Institute of Aeronautics and Astronautics Inc, AIAA, AIAA Aerospace Sciences Meeting, 2018, Kissimmee, United States, 18/1/8. https://doi.org/10.2514/6.2018-0048
Kasahara H, Matsuo A. The effect of shape on the aerodynamic and thermal performance of hypersonic projectiles launched by a ground-based railgun. In AIAA Aerospace Sciences Meeting. 210059 ed. American Institute of Aeronautics and Astronautics Inc, AIAA. 2018 https://doi.org/10.2514/6.2018-0048
Kasahara, Hirotaka ; Matsuo, Akiko. / The effect of shape on the aerodynamic and thermal performance of hypersonic projectiles launched by a ground-based railgun. AIAA Aerospace Sciences Meeting. 210059. ed. American Institute of Aeronautics and Astronautics Inc, AIAA, 2018.
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