边条翼布局双垂尾抖振特性与机理风洞实验研究

The wind-tunnel investigation of the characteristics and mechanism of twin-vertical tail buffet of leading-edge extension configuration

对两种平面形状的边条翼布局模型分别作了双垂尾抖振实验和涡流场激光片光源显示实验研究。抖振实验测量了两种模型双垂尾的翼根弯矩响应和翼尖加速度响应,涡流场显示实验记录了两种模型上典型位置上的涡流场发展状态。通过边条涡流场随迎角的发展和破裂特性与模型垂尾抖振响应特性的对比分析发现:(1)垂尾翼根弯矩、翼尖加速度响应随迎角的变化均与边条涡的发展状态、是否破裂以及破裂程度密切相关;(2)主翼后掠角较大的情况下,机翼前缘涡与边条涡相互干扰,不但加快了涡的破裂使得双垂尾抖振起始迎角减小,而且使得垂尾的抖振响应较大。

A wind tunnel investigation of buffeting on the vertical fin and a flow trualization experiment of a Twin-vertical-tailed configuration with Leadins-Edge Extension were conducted respectively in the Low Speed Wind Tunnel and NF- 3 wind tunnel at Northwestem Polytechnical Univemity. Two models with different plane shape wing were tested. The buffeting investigation measured the Root-Mean-Square （RMS） bending moment and RMS acce. lemtion of the vertical fin. The flow visualization provided the flow pictures at the critical longitudinal stations d both models, using the laser light sheet technique. Combining the vertical tail buffeting characteristics with the flow visualization pictures, the conclusion was come out： （1） the bursting of the vortex shed from LEX is the primary contributor to the twin-vertical tail buffet; （2）if the leading edge sweep-back-angle d the basic wing is large, the leading edge will generate a vortex which rotate at the same direction with LEX vortex. This result in the LEX vortex break down in advance and the vertical fin buffeting onset angle decline. At the same time, the break down flow contains the energy of both the LEX vortex and leading edge vortex, so that the buffeting response of the vertical fin becomes more strong.