| Summary: | 碩士 === 國立成功大學 === 航空太空工程學系 === 86 === The major purpose of this thesis is to simulate the vortex
shedding phenomenon of vortex flowmeter by a numerical method.
The numerical method uses three dimensional artificial
compressibility method to solve the incompressible flow field,
uses high order finite-volume technique for the convective terms
and handles the viscous terms by a finite volume tecnique. A
second-order, two step Runge-Kutta time integration is used
here. For unsteady problems the Crank-Nicolson method is used
in this thesis. An implicit residual smoothing is applied here
for improving convergence rate. Multi-zone grid technique is
applied in complex-domain computations.Two dimensional and three
dimensional bluff bodies and circular tubes were tested here to
verify reliability of the numerical method. After the above
tests, the results of two dimensional and three dimensional
models were compared each other. Finally, the phenomenon of flow
fields of the flowmeter with splitter plate and without the
splitter plate were compared and investigated here. Several
Reynolds numbers were chosen. Under these Reynolds numbers the
variations of , versus time were computed. And results were
analyzed by FFT to compute the dominated frequency. The results
indicate that the flowmeter with splitter plate will have more
clear dominated frequency.
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