| 摘要: | 為人所週知的，某些天氣現象會對飛行安全造成相當大的危害，例如低空風切、亂流、大雨和飛機積冰等現象。本研究的目的是欲藉由低空風切危害參數F參數為媒介，對在不良天候下飛行的飛機，其性能將會出現何種程度的衰減進行瞭解。
首先，本文將先建立三維的低空風切風場及三維的F參數，然後將其所計算出來的結果與代表亂流的T參數相加。其次將大雨和積冰情形下使用空氣動力學方程式所解算出的飛機性能衰減量，將其換算成等效的F參數，並將其與前者相加，從而得知在此種天候下飛機性能的總衰減量。在三維F參數的建立上，由於考慮到側風對飛機的影響，將採用二維的F參數加上角動量的影響，做為三維F參數之方程式；而在亂流的部分，則使用自行創造的T參數，其原理為將飛機在風場中所受到的三維加速度和角加速度變化予以非單位參數化。在大雨和飛機積冰的部分，則採用前人所建立的計算流體力學方法解析飛機的空氣動力係數，將其衰減的飛機性能計算出來，並換算出其相對應的F參數值。最後再將飛機可能遭遇的惡劣天氣現象之等效F參數和T參數相加成為FT參數，並應用新發展的FW參數，以求得在同時面對多種惡劣天氣現象下，飛機所受到的影響總合，並進而探討多種惡劣天氣存在時，單獨天氣現象對飛機所造成影響之比重。
台灣位處於世界最大海洋和最大陸塊之交界處，其天氣現象較許多國家更富有變化，近年來亦有多起因惡劣天候所造成之空難事故，故對足以威脅飛行安全之天候現象進行量化性且系統性的研究實有其必要性存在；本論文針對部分對飛機有重大影響惡劣天氣現象進行研究，以期可藉此對我國之飛行安全有所幫助，並能減少國人生命財產損失。
It is well known that some meteorological phenomenon will cause sizable danger to aviation safety, for example: low level windshear, turbulence, ice accretion and heavy rain, etc. The purpose of this research is to find out, by using existing low level windshear F-factor as the medium, the degrees of performance degradation for aircraft flying under different adverse weather conditions.
First of all, the study will set up the low level windshear 3-D wind field (including the side wind) and 3-D F-factor, then tally up the result with turbulence T-factor developed by our research group earlier. Secondly, take the aircraft performance amount calculated from heavy rain and ice accretion by using existing CFD techniques; convert it to an equivalent F-factor value. Add it with the previous result would get us the total performance amount under these weather conditions. At the end, tally up the different F-factor and T-factor values from the four adverse weather conditions that the aircraft might face, forming FT-factor and the newly created FW-factor, which will lead to the total aircraft performance degraded values in various adverse weather conditions. It is believed that the FW-factor represents a measuring weighting parameter for each adverse weather condition, which might co-exist with each other.
Taiwan is located at the intersection of the world’s largest ocean and land, which makes its meteorological phenomena full of varieties than that in many countries. In recent years, there are several accidents caused by adverse weather conditions. Therefore, it is necessary to investigate the meteorological phenomena that might be threat to aviation safety. Through the combining efforts in flight dynamics, aerodynamics, performance parameter developments, this study represents a first try in quantifying different adverse weather influences on aircraft performance degradation. It is hoped that the research results will be useful to local aviation safety community and help to eliminate some of the loss in lives and properties. |
