本研究主題之微風暴為造成許多次飛機失 事之主因。微風暴又名低空風切,產生於雷雨 或小塊雨雲之中,對起飛或降落之飛機將產生 極可怕的影響。由資料顯示出當微風暴接近地 面時,其流場結構頗類似於一暫態之渦旋狀環 流,而本文之目的即在於利用正式直接積分法 模擬出微風暴之流場結構,並以現有之噴射氣 流和環狀渦流模式相互比較。計算結果證實本 方法的確能夠在三千英呎以下的高度模擬出微 風暴之流場結構,並由於計算時間不長,仍然可以使用於飛行模擬器上。 Microbursts, suggested as primary causes of many aircraft fatal crashes, are the subject of this study. A microburst, or low-level intense wind shear, is generated by a thunderstorm or a small rain cloud, and presents hazardous conditions for aircraft during take-off and landing maneuvers. Recently released data show that a microburst resembles a transient vortex ring; the purpose of this research is to construct a vortex ring model for a microburst via the Direct Formal Integration (DFI) method and to compare its computed behavior with that of existing turbulent jet and vortex ring models. In addition to improved understanding of the physical nature of microbursts, this model can also be used for flight simulation and pilot training purposes. Results show that this model is also capable of producing microburst-like flow motion at altitudes below 3000ft, and is still efficient and suitable for flight simulation use.
中國航空太空學會第三十四屆學術研討會論文集(一)=Proceedings of the AASRC 34th Aeronautics and Astronautics Conference ( I)，頁93-99