微風暴曾經造成許多次飛機失事事件 ,本文之目的在於利用穩定及非穩定狀況下之 環狀渦旋流來模擬微風暴的流場。起始條件為 一突發之噴射氣流,在不同時刻之兩個環狀渦 旋流,其相互作用及流場示意圖將予以充份討 論。此計算所得之流場除可做為飛行訓練之用 外,且可增加吾人對於微風暴之了解。 Microbursts formed near airports during thunderstorm activities have been responsible for several major airliner crashes. This weather phenomenon features a sudden and very intense downflow that can cause even the most sophisticated aircraft to quickly lose altitude. Proper airline transport pilot training in flight simulators is an effective way of achieving greater safety to aircraft against microbursts. Both steady and unsteady multiple-vortex-ring models are developed to simulate microbursts. The models use an impulsive free jet as an input to provide the central axial velocity of the vortex rings and their mirror images. Wind velocity fields are plotted to display the calculation results. For unsteady flow, trajectory plots are also made to demonstrate how the locations of the two vortex rings vary in mid air as time advance. The flow pattern and the interaction between two vortex rings are discussed. The predicted penetration of the smaller vortex ring through the larger one, when they share a common central axis, is shown in one of the unsteady cases.
中國航空太空學會民國八十年學術研討會論文集=Proceedings of the 1991 Aeronautics and Astronautics Conference of the A=eronautical and Astronautical Society of the R.O.C.，頁261-273