由於溫室效應的影響，極端惡劣天氣變得相當頻繁，例如低空風切、颱風、冰或雪。當飛機起飛降落時會不幸遭遇大雨，因此在飛機設計時須考慮這些天氣因素的影響，而大雨對飛機所造成的氣動力損失則是正在進行中的研究主題且需要長遠的進行研究，但是除了本研究團隊近幾年曾經針對大雨對機翼性能分析有過分析之外，近10年來不論是在實驗或是在數值計算方面已鮮少有相關的研究。本研究首先對回顧前人所做的因大雨效應而使得飛機性能減低的研究並使用數值方法做進一步的探討，並使用NACA 64-210二維高升力翼剖面和現有的商用軟體FLUENT，大雨的模擬則是採用FLUENT內的二相流 (Two-Phase Flow)離散相的DPM模組(Discrete Phase Model)和改變表面粗糙度來完成並計算空氣動力特性的改變。 本研究首先進行乾淨翼剖面的驗證工作，並成功模擬出二維高升力翼剖面在大雨下的性能衰減，其衰減程度會隨著降雨量的增加而越大，而失速的情形也有提前發生的現象，研究發現升力係數減少、阻力係數增加的程度與Bezos 實驗結果相近。本研究所得到的量化資料能夠能對航空業上有所助益，長遠來說，可以使得飛機飛行的更安全。 Global warming has led to extreme weather around the world frequently such as low level wind shear, typhoon, ice/snow etc. If aircraft taking-off and landing will unavoidably meet with the heavy rain, then aircraft designer must put these severe weather influences into considerations in the conceptual design phase. Aerodynamic influences due to heavy rain are still the on-going research subject, and needs further investigation. But for the past decade there are neither experimental nor numerical researches about heavy rain except our research team conducted in recent years. In this thesis, we first review some research finding of heavy rain effects on the aerodynamic performance degradation. Secondly, commercial CFD package FLUENT and preprocessing tool Gambit is used as our main analysis tools, and the simulation of rain is accomplished by using Two-Phase Flow approach’s Discrete Phase Model (DPM) and surface roughness provided by FLUENT. The results show that this research successfully simulates the aerodynamic investigation of high-lift airfoil under the influence of heavy rain effects, the doubts or errors in the previous numerical and experimental works are also revealed. The degradation rate increases with the rain rate, and the premature stall phenomenon is also discovered. It is expected that the quantitative information gained in this thesis could be useful to the operational airline industry, and greater effort should put in this direction to further improve modern transport aircrafts safety.