| Summary: | 碩士 === 淡江大學 === 航空太空工程學系碩士班 === 98 === The goal of aircraft design is to achieve safe and efficient flight. In the world of civilian air transport, efficient, economically attractive configurations are urgently needed. As for civilian commercial aircrafts, studies have shown remarkable performance improvements for the Blended Wing Body (BWB) over conventional subsonic transport. On the other hand, global warming has led to extreme weather around the world frequently, if aircraft taking-off and landing will unavoidably meet with the strong crosswind or/and heavy rain, then aircraft designer must put these severe werather influence into considerations in the conceptual design phase phase. One way to investigate the BWB airplane performance degradation is through CFD calculation.
The detrimental crosswind effects to Blended Wing Bod aircraft longitudinal, lateral and directional stability situation will be presented in this study. The speed of crosswinds considered here are 10m/s, 20m/s and 30m/s. Comparing with Boeing 747-100, no matter BWB is static stable or not, its stability derivative values under crosswind are always smaller than Boeing 747-100, representing the intrinsic nature of BWB static unstable tendency. Also, the heavy rain influence of different rain rates is that the lift coefficient is decreased and drag coefficient is increased at all different angle of attack spectrum. Comparing the different rain rates, liquid water content 39 g/m3 is more influential than 25 g/m3, with maximum reduction of lift coefficient is at angle of attack 0 degree and maximum increase of drag coefficient is at angle of attack 6 degree.
In this study, Fluent is used as a simulation tool, the structure grid is chosen and generated by Gambit, and the standard M6 wing is first validated to ensure this simulation process is correct. This study hope to recognize and comprehend the basic aerodynamic performance for Blended Wind Body aircraft under severe weather situation, and the information gained here will be helpful for future transport aircraft designers.
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