A Study on the Unsteady Aerodynamics of Projectiles in Overtaking Blast Flowfields

C.K.Muthukumaran,G.Rajesh,Vincent Lijo,Heuy Dong Kim 한국추진공학회 2011 한국추진공학회 학술대회논문집 Vol.2011 No.11

A projectile that passes through a shock wave experiences drastic changes in the aerodynamic forces. These sudden changes in the forces are attributed to the wave structures produced by the projectile-shock wave interaction. A computational study using moving grid method is performed to analyze the effect of the projectile-shock wave interaction. Cylindrical and conical projectiles have been employed to study such interactions. This sort of unsteady interaction normally takes place in overtaking blast flow fields. It is found that the overall effect of overtaking a blast wave on the unsteady aerodynamic characteristics is hardly affected by the projectile configurations. However, it is noticed that the projectile configurations do affect the unsteady flow structures and hence the drag coefficient for the conical projectile shows considerable variation from that of the cylindrical projectile. The projectile aerodynamic characteristics, when it interacts with the secondary shock wave, are analyzed. It is also observed that the change in the characteristics of the secondary shock wave during the interaction is different for different projectile configurations.

Monte Carlo Calculation for Production Cross-Sections of Projectile’s Isotopes from Therapeutic Carbon and Helium Ion Beams in Different Materials

Quazi Muhammad Rashed Nizam,Asif Ahmed,Iftekhar Ahmed 대한방사선방어학회 2023 방사선방어학회지 Vol.48 No.4

Background: Isotopes of the projectile may be produced along the beam path during the irradiation of a target by a heavy ion due to inelastic interactions with the media. This study analyzed the production cross-section of carbon (C) and Helium (He) projectile’s isotopes resulting from the interactions of these beams with different materials along the beam path. Materials and Methods: In this study, we transport C and He ion beams through different materials. This transportation was made by the Monte Carlo simulation. Particle and Heavy Ion Transport code System (PHITS) has been used for this calculation. Results and Discussion: It has been found that 10C, 11C, and 13C from the 12C ion beam and 3He from the 4He ion beam are significant projectile’s isotopes that have higher flux than other isotopes of these projectiles. The 4He ion beam has a higher projectile’s isotope production crosssection along the beam path, which adds more impurities to the beam than the 12C ion beam. These projectile’s isotopes from both the 12C and 4He ion beams have higher production crosssections in hydrogenous materials like water or polyethylene. Conclusion: It is important to distinguish these projectile’s isotopes from the primary beam particles to obtain a precise and accurate cross-section result by minimizing the error during measurement with a nuclear track detector. This study will show the trend of the production probability of projectile’s isotopes for these ion beams.

Parametric study of a projectile launched by a compressed air cannon

Woojin Sung,Ji Hoon Kim,Kyeong sik Jang,Thi Thanh Giang Le,Jeonglae Kim,Dong Hyeon Kim,이형순,Jaiyoung Ryu 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.11

The principle of the compressed air cannon is that compressed air in the reservoir expands rapidly to propel the projectile. Previous studies assume that the tube pressure in front of the projectile is constant because the tube pressure was too low compared to the compressed air pressure in the reservoir. However, when the projectile actually travels in the tube, a compression wave is generated in front of the projectile. In this study, the theoretical prediction for the velocity of the projectile was performed using the tube pressure in front of the projectile affected by the compression wave as a variable. The results show that the maximum velocity decreases compared to previous studies. This difference from the constant tube pressure assumption cases becomes larger as the maximum velocity of the projectile increases. The theoretical prediction considering the compression wave shows a more realistic deceleration than when the tube pressure is constant.

Effect of Projectile Incident Angle on Penetration of Steel Plates

천준민,최영식 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.17 No.12

High speed impacts are complex phenomena influenced by various parameters. To predict the structural damage caused by a high speed impact, it is necessary to investigate the effect of various impact conditions, such as the incident angle, the nose shape and diameter of the projectile, and the material and thickness of the plate, on the behavior of the structures. Although the projectile incident angle considerably influences the behavior of steel structures, studies on this subject have been limited. Thus, this study investigates the effect of the projectile incident angle on the deformation of the steel plate and the penetration behavior of the projectile. It was found that the projectile incident angle significantly influences the plate deformation and the angle, velocity, and kinetic energy of the projectile.

텔레메트리 시험을 이용한 날개안정형 발사체의 회전감쇠공력계수 실험적 산출 방법

김진석,김경훈,최재현 한국군사과학기술학회 2018 한국군사과학기술학회지 Vol.21 No.6

Accurate aerodynamic characterization of projectile is crucial for successful development of munition. The aerodynamic characterization of fin stabilized projectile is more difficult than characterization of traditional symmetric ballistic projectile. Instrumented free flight experiments were conducted to quantify rolling behavior of fin stabilized projectile. The instrumented projectiles were launched from a rifled tube and the onboard sensor data were acquired through a telemetry transmitter. Roll rate was measured for fin stabilized projectile by means of an angular rate sensor. And, roll damping coefficients were estimated from onboard sensor data acquired during gun firing and trajectory analysis of mathematical model.

A Theoretical Study for the Design of a New Ballistic Range

Rajesh G.,Lee J.M.,Back S.C.,Kim Heuy-Dong The Korean Society of Mechanical Engineers 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.7

The ballistic range has long been employed in a variety of engineering fields such as high-velocity impact engineering, projectile aerodynamics, creation of new materials, etc, since it can create an extremely high-pressure state in very short time. Of many different types of ballistic ranges developed to date, two-stage light gas gun is being employed most extensively. In the present study, a theoretical work has been made to develop a new type of ballistic range which can easily simulate a flying projectile. The present ballistic range consists of high-pressure tube, piston, pump tube, shock tube and launch tube. The effect of adding a shock tube in between the pump tube and launch tube is investigated. This improvement is identified as the reduction in pressures in the high pressure tube and pump tube while maintaining the projectile velocity. Equations of motions of piston and projectile are solved using Runge-Kutta methods. Dependence of projectile velocity on various design factors such as high pressure tube pressure, piston mass, projectile mass, area ratio of pump tube to launch tube and type of driver gas in the pump tube are also analyzed. Effect of various gas combinations is also investigated. Calculations show that projectile velocities of the order 8 km/sec could be achieved with the present ballistic range.

A Theoretical Study for the Design of a New Ballistic Range

G. Rajesh,J. M. Lee,S. C. Back,Heuy Dong Kim 대한기계학회 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.7

The ballistic range has long been employed in a variety of engineering fields such as high-velocity impact engineering, projectile aerodynamics, creation of new materials, etc, since it can create an extremely high-pressure state in very short time. Of many different types of ballistic ranges developed to date, two-stage light gas gun is being employed most extensively. In the present study, a theoretical work has been made to develop a new type of ballistic range which can easily simulate a flying projectile. The present ballistic range consists of high-pressure tube, piston, pump tube, shock tube and launch tube. The effect of adding a shock tube in between the pump tube and launch tube is investigated. This improvement is identified as the reduction in pressures in the high pressure tube and pump tube while maintaining the projectile velocity. Equations of motions of piston and projectile are solved using Runge-Kutta methods. Dependence of projectile velocity on various design factors such as high pressure tube pressure, piston mass, projectile mass, area ratio of pump tube to launch tube and type of driver gas in the pump tube are also analyzed. Effect of various gas combinations is also investigated. Calculations show that projectile velocities of the order 8 ㎞/sec could be achieved with the present ballistic range.

Numerical Prediction of the Impact Fracture of a Projectile Through Oblique Target

양주석,최민국,김천곤 한국항공우주학회 2023 International Journal of Aeronautical and Space Sc Vol.24 No.3

In modern warfare, oblique penetration is frequently observed when a penetration warhead mounted on a guided missile hits the target. When oblique penetration occurs on hard targets, such as reinforced concrete, the projectile experiences complex stress states along with tensile and compression stresses that can result in the deformation and fracture of the projectile. Therefore, the survivability of the projectile should be determined at the design phase. Structural survivability was assessed here through a correlated simulation considering a case where the projectile was fractured while penetrating into a 30° inclined concrete target at 333 m/s. For correlated simulation, we obtained the dynamic constitutive equation and fracture properties of the projectile material (AISI4340 steel) up to a strain rate of 1500 s−1. Furthermore, concrete material coefficients related to the strain rate sensitivity were calibrated using the test database. Computational analysis result agreed well with the actual test result.

Flow separation control of two kinds of microvortex generators for a supersonic spinning projectile

Jie Ma,Zhen-gui Huang,Zhihua Chen,Da-wen Xue,Jun-li Han 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.1

Previous studies have shown that Microvortex generators (MVGs) can effectively control the flow separation of supersonic boundary layer. To improve the flight stability of a spinning projectile, two kinds of MVGs, micro ramps and vanes, are applied to control the flow separation of an original standard 155 mm projectile, respectively. Numerical simulations were performed with the use of Detached eddy simulation (DES) method, and the flow fields of the projectile with and without micro MVGs were simulated, the characteristics of the boundary layer and aerodynamic data of three cases were compared and discussed. The numerical results reveal that the effect of the MVGs control is obvious, but their mechanisms are different, and the vanes are more effective than the ramp in the boundary layer control. However, they can both improve the lift and pitching moment of the projectile, and eliminate their oscillations; as a result, its flight stability and firing dispersion can be enhanced. Our results can provide important guidance for improving the flight quality of supersonic projectiles.

천음속/초음속 Projectile 에 관한 실험적 연구

이중근(Jung Keun Lee),Fanshi Kong,Jianguo Sun,김희동(Heuy Dong Kim),구자예(Ja Ye Koo) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10

Two-stage light-gas gun has a large number of applications in various fields of engineering. A two-stage light-gas gun can produce an extremely high pressure in a very short interval of time. In general, the twostage light-gas gun is made up of a high pressure tube, a compression tube and a launch tube, each stage being separated by diaphragms. In the present study, by using a technique schlieren visualization, visualize to the projectile of launched by two-stage light-gas gun. Experiments are carried out to investigate visualization of the flow around the projectile according to angle and mach number of projectile. As the result, small angle and large mach number of projectile were created a strong shock wave.