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축소-확대 노즐과 플러그 노즐의 개념설계 및 전산유체해석
장근진(K.-J. Jang),김소연(S.-Y. Kim),김성돈(S.-D. Kim),최정열(J.-Y. Cho),김명호(M.-H. Kim),권민찬(M.-C. Kwon) 한국추진공학회 2013 한국추진공학회 학술대회논문집 Vol.2013 No.12
압축성 유체 이론에 기초하여 고속 추진 시스템을 위한 초음속 노즐의 개념 설계 프로그램을 작성하였으며, 이를 이용하여 축대칭 조건의 축소-확대 노즐 및 플러그 노즐의 형상을 설계하였다. 설계된 형상에 대하여 0, 4, 10, 20 km 고도 조건에 노즐 유동 및 배기 유동에 대한 전산 유체역학 해석을 수행하여 이론 및 실험 결과와 비교한 검증 유동 특징을 살펴보았다. A conceptual design program of supersonic nozzles is developed high-speed propulsion system based on the theory of compressible fluid dynamics. A convergent-divergent (C-D) nozzle and a plug nozzle are designed using the program in axi-symmetric configuration. CFD analyses are carried out using the designed configuration for the verification of the design by comparing the results with the theoretical and experimental results and for the investigation of the plume flow field at 0, 4, 10, 20km altitude conditions.
최정열(J.-Y. Choi),장근진(K.-J. Jang),김성돈(S.-D. Kim),정인석(I.-S. Jeung),이종국(J.-K. Kim) 한국추진공학회 2013 한국추진공학회 학술대회논문집 Vol.2013 No.12
본 연구에서는 극초음속 노즐 설계를 위한 설계 절차를 수립하였다. 노즐 목에서 확산 영역까지 특선곡선해법을 이용하여 기본 설계를 수행하며, 기본 설계에 대한 격자를 작성하여 MOC 설계를 확인하기 위한 비점성 CFD 해석을 수행한다. 비점성 결과를 바탕으로 점성 해석을 수행하여 기본 형상에 대한 경계층을 보정하여 격자를 다시 생성한 후, 결과 확인을 위한 점성 해석을 다시 수행한다. 전 과정은 자동 일괄 처리토록 작성 되었으며, 여러 경계층 보정 방법에 따른 결과들을 비교 검토 하였다. A design procedure is established to design hypersonic nozzles. The basic design is carried out by the MOC for the throat region to the divergence region. Grid generation is carried out for the basic design, followed by the inviscid CFD analysis to confirm the MOC design. The inviscid solution is used as an initial condition for viscous simulation. Then, boundary layer thicknesses are evaluated from the results viscous solution. The BLC is made for the basic geometry and the computational grid is reconstructed. Finally, viscous simulation is carried out again to confirm the BLC. All this procedure is made automatically by using the batch processing. Various BLC approaches were compared through the present study.
멀티코어 시스템에서 thread 수에 따른 CFD 코드의 OpenMP 병렬 성능
김종관(J.-K. Kim),장근진(K.-J. Jang),김태영(T.Y. Kim),최정열(J.-Y. Choi) 한국전산유체공학회 2012 한국전산유체공학회 학술대회논문집 Vol.2012 No.11
OpenMP is becoming more and more useful as a simple parallel processing paradigm on SMP (Shared Memory Multi-Processors) computing environment with the development of multi-core processors. However, very few data is publically available regarding the OpenMP performance in CFD (Computational Fluid Dynamics). In the present study a CFD test suite is prepared for the performance evaluation of OpenMP on various multi-core systems. The test suite is composed of two-dimensional numerical simulations for inviscid/viscous and reacting/non-reacting flows using three different levels of grid systems. One to five test runs were carried out on various systems from dual-core dual threads to 16-core 32-threads systems by changing the number of threads engaged for each test up to 80. The results exhibit some interesting results and the lessons learned from the tests would be quite helpful for the further use of OpenMP for CFD studies using multi-core processor systems.
멀티코어 시스템에서 쓰레드 수에 따른 CFD 코드의 OpenMP 병렬 성능
김종관(J.-K. Kim),장근진(K.-J. Jang),김태영(T.Y. Kim),조덕래(D.-R Cho),김성돈(S.-D. Kim),최정열(J.-Y. Choi) 한국전산유체공학회 2013 한국전산유체공학회지 Vol.18 No.1
OpenMP is becoming more and more useful as a simple parallel processing paradigm on SMP (Shared Memory Multi-Processors) computing environment with the development of multi-core processors. However, very few data is available publically regarding the OpenMP performance in CFD (Computational Fluid Dynamics). In the present study a CFD test suite is prepared for the performance evaluation of OpenMP on various multi-core systems. The test suite is composed of two-dimensional numerical simulations for inviscid/viscous and reacting/non-reacting flows using three different levels of grid systems. One to five test runs were carried out on various systems from dual-core dual threads to 16-core 32-threads systems by changing the number of threads engaged for each test up to 80. The results exhibit some interesting results and the lessons learned from the tests would be quite helpful for the further use of OpenMP for CFD studies using multi-core processor systems.