利用隱式大渦流紊流模式計算氣動噴流噪音

Abstract

隨著生活品質的提昇，噪音問題越益受到重視，其中又以流體所誘導的氣動噪音最為複雜。本計畫將發展氣動噪音的計算方法用以分析與改善噪音問題。由於計算聲場時，需先計算可壓縮紊流流場以得相關的聲源資訊，因此於本計畫的第一年將先發展大渦流(LES)紊流全域流場計算方法，過去的研究多利用顯示紊流模式(explicit turbulence model)為次格點尺度模型(SGS model)。然而此法耗費過多計算時間且應用範圍受限，本研究將發展隱示紊流模式(implicit turbulence model)做為次格點尺度模型，此法不僅撰寫容易，且大幅提升計算效率，適用性更加廣泛。

With the improvement of the life quality, the noise induced by aeroacoustic becomes one of the most important and complicated problems of the noisecontrol. The computational methods of the aeroacousitcs used to analyze and improve the noise problems will be developed in this subject. Before resolving the problems of the aeroacoustics, the computational method called large eddy simulation(LES) for compressible turbulence in all speed flows will be developed first. In the previous literatures, the explicit turbulence model was usually used to be a subgrid scale model. However, this kind of models is not efficient and will be limited in practical applications. In order to overcome the problem mention above, the implicit turbulence model for LES which is efficient, easily programmed and wide applications will be developed in the present study.