|作品名稱（其他語言）||A Study of Aircraft Aerodynamics under Heavy Rain and Ice Accretion|
|著者||宛同; 袁堂鈞; 李浚傑; 吳仕偉|
此研究之目的著重於回顧此地區最新的發現以及利用新的解析方法去計算當飛機遭遇大雨或積冰時空氣動力減少的結果，期望能達到一般的結論。最重要的是此科學上的結果能提出於航空界中，以期在決定性關鍵中能扮演好它的角色。經由本工作將會得到一些資料並能對航空公司運作上有所助益，長遠來說，以期使得飛機飛的更安全些。;The detrimental effects of some meteorological phenomenon such as wind shear, thunderstorm, ice/snow etc, to aviation safety are relatively well known. But aerodynamic influences due to heavy rain are still the on-going research subject, and needs further investigation. This research first review some research finding of heavy rain effects on aerodynamic performance degradation. Then an analytical method to compute the two-dimensional heavy rain condition is introduced and some preliminary results are discussed. Finally, the classical flight dynamics equations are solved with rain and rain/gust influences in the approach to land and the touch down to brake phases. It is felt that the quantitative information gained in this work could be useful to the operational airline industry, and greater effort should put in this direction to further improve aviation safety. Through the combining efforts in weather forecast, radar technology, data communication, and pilot training awareness, aviation accidents due to these phenomena have decrease drastically in last decade. On the other hand, the adverse efforts of gust wind and heavy rain on aircraft performance and aerodynamic efficiency remain somewhat unclear and even contradictory, and new research results are still reporting from aviation research institutes or universities.
The three causes lead to Airplane crash that include human, mechanism, and the weather. Ice accretion, the topic we want to discuss in this article, categorized into the weather. Broadly speaking, the reason of ice accretion was that temperature of air lower than freezing point, and droplet exist in supercooled water. When droplet impact on airfoil, it accretes. Bowyer's unstructured grids scheme is useful to generated grids. It will generate grids automatically only by some inner or outer boundary points. It's easier to add or eliminate specific grid, and thus more suitable for complex geometry, just like ice accretion shapes. The numerical scheme employed is the typical Roe's scheme on Euler equations, and the 4 th order Runge-Kutta time stepping method is also used to accelerate the convergence rate. Droplet motion equation and tell droplet if impact the airfoil or not, based on the results of solver. Apply ice accretion analysis, the ice accretion shape come out. After that, the grids regenerate, so do flowfield and ice accretion. It lasted repeatJy until the time we set. The ice accretion results show that the trend of ice accretion is correct, but ice accretion profile and ice accretion thickness is not as good as we expected. Several improvements have been presented.
The purpose of this project is first to review the latest findings in this area, and through a new analytical method to compute the aerodynamic degradation effects in heavy rain and ice accretion conditions, it is hoped that a general conclusion can be reached. Most important is that these scientific results should pass on to the aviation community, and plays its role at some decisive moments.