http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Vu Dan Thanh Le (검색결과 2 건)
- 무료
- 기관 내 무료
- 유료
-
Vu Dan Thanh Le,Anh Tuan Nguyen,Lac Hong Nguyen,Ngoc Thanh Dang,Ngoc Doan Tran,한재흥 한국항공우주학회 2021 International Journal of Aeronautical and Space Sc Vol.22 No.5
This paper explores the effectiveness of spin motion in mitigating the flight dispersion of a two-stage solid-propellant rocket model due to thrust misalignment. The aerodynamic coefficients of the rocket model are obtained by the use of a panel method and semi-empirical equations. A simulation program is developed to solve the equations of motion while considering the variations of the inertial parameters. Monte Carlo simulation techniques are applied to provide statistical data that are used to analyze the relationship between the spin motion and flight dispersion. The spin motion is generated by canting the fins to generate the axial aerodynamic moment. The results show that thrust misalignment at the first stage of the rocket has a great impact on the dispersion of rocket flight. By canting the first-stage fins at a relatively large angle to create the spin motion right after launch, the dispersion area of the payload-release location can be minimized considerably. However, thrust misalignment as well as the fin cant angle at the second stage appear to have insignificant effects on the rocket flight trajectory. On the other hand, canting the fins of the second stage at a large angle may lead to an increase in the spin rate, which may be harmful to the rocket operation. The paper also shows the variation of the dispersion characteristics of rocket flight when the fin size is modified.
-
Trajectory analyses of uncontrolled circular parachutes in random spatial wind fields
Thanh Dong Pham,Anh Tuan Nguyen,Vu Dan Thanh Le,Trung Kien Nguyen 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.8
The present paper explores the trajectories of two uncontrolled circular parachute models which differ in size and mass in random spatial wind fields. The wind velocity components were generated through three-dimensional inverse fast Fourier transforms; and the correlations of the simulation data compared with the theoretical functions to confirm the accuracy of the wind model. The parachute systems are modelled as six-degrees-of-freedom rigid bodies, on which the aerodynamic forces and moments are applied. The dynamics model was validated before being used to study the drop trajectories of the parachute systems in spatial wind fields. Analyzing the drop trajectories and the impact point dispersion characteristics of the two parachute systems, the paper shows that the smaller one oscillates at a higher frequency and is affected more strongly by the wind. While descending at low altitude, there could be resonance between the dynamics of the larger parachute model and the wind turbulence. Moreover, it is found that the use of simplified vertical wind profiles, which include only the variation of the wind velocity against the altitude, may cause significant error in the simulation results.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
