地面效应对舰载机起飞特性的影响

众所周知,地面效应(以下简称“地效”)对近地飞行时飞机的迎角、升力、阻力和洗流场都有明显影响,而尤以升力效应对起飞特性的影响最为严重。舰载机在飞离甲板瞬间地效升力突然损失,可能导致“下沉”现象,直接影响到飞机的安全。本文的工作包括两个主要方面:1.在总结现有文献的基础上,提出在不同离陆高度时全机气动参数的计算方法。2.研究舰载机在飞离甲板瞬间因突然失去地效而导致起飞特性的变化,特别是下沉问题。算例表明,地效使得甲板起飞和地面起飞特性有明显区别,是舰载机设计中必须考虑的重要问题。

Ground Effect on the Take-off Characteristics of Sea-Based Aircraft

To meet the strict demands for the sea-based aircraft during take-off and landing phase is the most important flight dynamic problem to be solved. One of the main differences between take-off from the ground and from the deck is that ground effect loses gradually after liftoff from the ground,while it loses suddenly in case of liftoff from the deck. As is known to all, the ground effect has considerable influence on drag, down-wash field behind the wing, and specially on lift. The sudden loss of lift may cause so called "sink" for sea-based aircraft at the instant of liftoff from the deck,which may cause safe problem for aircraft. Two important aspects are included in this thesis:1. A. synthetic method is presented here to estimate ground effects on aerodynamic forces and moments of a complete aircraft.2. The change of take-off characteristics, especially the sinkage, caused by sudden loss of ground effect has been studied and a numerical method concerned has been developed.