| Summary: | 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.
|
|---|
