# 발사초기 단계에서 발사체의 마하수, 받음각 및 노즐 효과에 따른 공력특성 연구

• Jeong, Taegeon (Department of Mechanical Engineering, Graduate School, Sunchon National University) ;
• Kim, Sungcho (School of Mechanical and Aerospace Engineering, Sunchon National University) ;
• Choi, Jongwook (School of Mechanical and Aerospace Engineering, Sunchon National University)
• Accepted : 2019.04.18
• Published : 2019.04.30

#### Abstract

Aerodynamic characteristics for a launch vehicle are numerically analyzed with various conditions. The local drag coefficients are high at the nose of the launch vehicle in subsonic region and on the main body in supersonic region because of the induced drag and the wave drag, respectively. The drag coefficients show the similar trend with the angle of attack except zero degree. However, the more the angle of attack increases, the more dependent on the Mach number the lift coefficient is. The body rotation for the flight stability destroys the vortex pair formed above the body opposite to the flight direction, so the flow fields are more or less complicated. The drag coefficient of the launch vehicle at sea level is about three times larger than that at altitude 7.2 km. And the thrust jet at the nozzle causes to reduce the drag coefficient compared with the jetless transonic flight.

#### File

Fig. 1. Geometry of launch vehicle

Fig. 2. Unstructured hexa grid system

Fig. 3. Drag coefficients with invicid and various turbulent models at Ma=0.8

Fig. 4. Distributions of Mach number and pressure coefficient

Fig. 5. Distributions of Mach number with angle of attack at Ma=0.8

Fig. 6. Variations of drag coefficients on body and tail regions with Mach number

Fig. 7. Variations of drag coefficients with angle of attack and Mach number

Fig. 8. Distributions of pressure coefficient on tail surface of launch vehicle at Ma=0.8 (left: AOA=2.5°, right: AOA=5.0°)

Fig. 9. Variations of lift coefficients with angle of attack and Mach number

Fig. 10. Distribution of Mach number over launch vehicle body (α=7°, ω=600rpm, Ma=0.2)

Fig. 11. Distribution of streamlines over launch vehicle body (α=7°, ω=600rpm, Ma=0.2)

Fig. 12. Distribution of Mach number at sea level(left) and altitude of 7.2km(right)

Fig. 13. Distribution Mach number over launch vehicle with nozzle

Fig. 14. Distribution of Mach number over launch vehicle with thrust

Table 1. Comparison of the drag coefficient at sea level and altitude of 7.2km

Table 2. Drag coefficients with nozzle and thrust

#### References

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