| Summary: | 碩士 === 國立成功大學 === 機械工程學系碩博士班 === 98 === The evolution of impinging plane jets are simulated by discrete vortex method. The physical phenomena of impinging plane jets are carefully studied in the present study.
The numerical scheme of vortex method with random walk is used to simulate the viscous flow field of impinging plane jets. For the boundary condition processing, the panel method is also included to construct the solid walls of the impingement and confinement plates. In the solid boundaries ,the vortices are emitted outside to satisfy the no slip requirement.
At first, we validate the properties of impinging jets. The results show that the flow pattern can be divided into three characteristics regions : (1) free jet region, (2) impingement region, and (3) wall jet region. The free jet region has the similarity of Gaussian distribution. In addition, we can obtain the development of boundary layer and the similarity of velocity show in good agreement with Glauert theoretical solution in wall jet region. The numerical results are reasonable and consistent with those of available literatures. Then the investigation of the flow field characteristics with different nozzle-to-surface spacing and Reynolds numbers are presented. The results indicate that the larger values of nozzle-to-surface spacing accompany with the larger amplitude of flapping motion at the same Reynolds number. Moreover, the recirculation pattern will occur in wall jet regions at low Reynolds number.
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