The Study of Complex Geoemtry Application by Modified Bowyer's Grid Generation Method

• Main Authors: Chen, Shr-Chang, 陳世昌
• Other Authors: Wan Tung
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/45534064721078319965

碩士 === 淡江大學 === 航空太空工程學系 === 86 === It is a well known fact that the quality of grid points is very important in the field of computational fluid dynamics, and there are generally four different kinds of grid generation methods * namely multiblock, unaligned, overlapping, and unstructured methods. Among them, the unstructured grids are generated by some basic geometric or algebraic principles. It*s easier to add or eliminate specific grid, and thus more suitable for dynamic or complex geometry problems. The work done in this thesis is to use the modified Bowyer*s scheme to construct 2-D airfoil grids and using flow solver to solve for several complex geometry cases. The modifications made in Bowyer*s scheme are aspect ratio/minimum area check, boundary vertex check, local grid reconstruction, average area refinement, and artificial point addition, etc. The numerical scheme employed is the typical Roe*s scheme on Euler equations, and the 4th order Runge-Kutta time stepping method is also used to accelerate the convergence rate. The computational cases tested are NACA0012 airfoil, airfoil with flap, and airfoil with slat and two flaps. The influence of grid quality on flow results is also been tested. Finally, several aviation safety problems such as gust effect, airfoil ice shedding, and flap that can not fully extend, are implemented in this work. For aviation and airline industries, it is felt that the results of these aviation safety problems can be used as a qualitative reference in the decision making process.