| Summary: | 碩士 === 國立屏東科技大學 === 車輛工程系碩士班 === 92 === This thesis plans to use a code that combines fluid and acoustic simulation. The parameters in the near field of sound are computed by FLUENT that is a CFD solver with various turbulent models and the far field sound intensity, that are governed by the Ffowcs-Williams and Hawkins equation (FW-H). There are three steps in the task. The first stage is to demonstrate the numerical package to predict aero-noise of the incompressible flow, through simple 3D geometry sample models are used for validation. The second stage is to reform the numerical package accuracy and efficient, and apply to side view mirror and road vehicle. The present simulation results are found to be in good agreement with the published experimental results. At engineering environment, DES model is an acceptable technique except LES model predicting aero-noise. Aero-noise of rough side view mirror is louder than smooth one.The results indicate that the installation of an appropriately angled tail fin reduces the aerodynamic lift coefficient, and hence improves the vertical stability of the vehicle under high speed driving conditions. Furthermore, it is shown that the use of an end plate reduces the noise profile behind the car. The present steady also proposed an optimal tail fin / end plate configuration, which possesses enhanced aerodynamic characteristics and aero-acoustic properties, and hence improves driver safety and comfort.
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