| Summary: | 碩士 === 國立成功大學 === 航空太空工程學系 === 82 === The purpose of this research is to analyse and simulate the
terrain effect on aircraft noise, we are looking forward to be
helpful on analyzing aircraft noise of Taiwan. Terrain effect
on aircraft noise is to solve scattering problem. For general
obstacle shapes, the most popular numerical method on
scattering problem is the boundary element method (B.E.M.), yet
it is difficult on implementation and it needs modifications
for the obstacle shape with shape edge or at some
characterestic wavenumbers. We use the method of fundamental
solution (M.F.S.) to solve scattering problem in this research.
M.F.S. is developed much later then B.E.M., it won't add
burdden on implementation at characterestic wavenumber occured
in B.E.M., so it is suitable for solving general scattering
problem. This method uses finite simulation point sources
inside obstacle to simulate the scattering field. Put our
numerical result and analytical solution or solution of B.E.M.
into comparison, if the chosen grid points on on obstacle
reaches some amount we need only small quantity of simulation
point sources to simulate scattering field. In this research it
is assume that airplane is a moving point source, using M.F.S.
combined with the boundary condition of half plane and finite
impedence to simulate the aircraft noise field. A simulation
example of aircraft noise contour plot is given.
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