원추곡선을 이용한 평면곡선의 표현 기법

Maste

Convergence Study of the Multigrid Navier-Stokes Simulation : Ⅱ. Implicit Preconditioners

본 연구는 다중 격자 Navier-Stokes 방정식 해석의 수렴성 향상을 그 목적으로 한다. 다중 격자 기법의 성능 향상을 위해 최근 많이 사용되고 있는 예조건화된 다단계 시간 전진 기법의 효율성 향상을 위한 연구를 수행하였다. 압축성 유동장 해석시 자주 이용되는 ADI 예조건자와 DDADI 예조건자의 수렴 특성 비교 연구를 수행하였다. 2차원 압축성 난류 유동장 해석에 적용함으로써 DDADI 예조건자가 ADI 예조건자에 비해 우수한 수렴특성을 가짐을 확인하였고, 이를 통하여 Fourier 해석을 통한 예조건화 특성 연구와 일치하는 수렴 특성을 확인하였다. Spalart-Allmaras(S-A) 난류 모델과 Baldwin-Lomax (B-L) 난류 모델의 적용을 통해 난류 모델에 따른 수렴성 비교를 수행하였다

Study of Aerodynamic Design Optimization Using Genetic Algorithm

Genetic Algorithm(GA) is applied to aerodynamic shape optimization and demonstrated its merits in global searching ability and the independency of differentiability. However, applications of GA are limited due to slow convergence rate, premature termination, and high computing costs. The present aerodynamic designs such as wing shape optimizations using GA have seldom been applied because of high computing costs. This paper has two objects; improvement of the efficiency of GA and application of GA into aerodynamic shape optimization for 2D and 3D wings. The study indicates that GA can be applied to aerodynamic design and its performance is comparable to traditional design methods.슈퍼 컴퓨팅 센터의 전략과제로 지원을 받아 수행된 연구의 결

PARALLEL IMPROVEMENT IN STRUCTURED CHIMERA GRID ASSEMBLY FOR PC CLUSTER

Parallel implementation and performance assessment of the grid assembly in a structured chimera grid approach is studied. The grid assembly process, involving hole cutting and searching donor, is parallelized on the PC cluster. A message passing programming model based on the MPI library is implemented using the single program multiple data(SPMD) paradigm. The coarse-grained communication is optimized with the minimized memory allocation because that the parallel grid assembly can access the decomposed geometry data in other processors by only message passing in the distributed memory system such as a PC cluster. The grid assembly workload is based on the static load balancing tied to flow solver. A goal of this work is a development of parallelized grid assembly that is suited for handling multiple moving body problems with large grid size