双垂尾抖振实验研究

Wind Tunnel Investigation of Twin-Vertical-Tails Buffet

边条翼双垂尾布局是新一代战斗机的主要布局形式,这种气动布局可能引起双垂尾抖振,是飞机设计中的一个技术关键。边条翼布局双垂尾的抖振特性实验研究在西北工业大学低速风洞进行,测试迎角范围:0°～50°。实验还将垂尾位置前移了30mm(15.8%垂尾平均气动弦长)进行测量,并将垂尾前后2种位置的响应进行了对比分析。对2种模型都测量了垂尾的根部弯矩响应和翼尖加速度响应的时间历程,经数据处理得出弯矩和加速度脉动响应的均方根值及功率谱密度分布。实验结果表明:1抖振主要发生在一弯模态;2当迎角达到20°后,翼根弯矩响应和翼尖加速度响应都急剧增加,抖振起始迎角约为20°;3抖振响应在迎角27～40°之间最大;4垂尾前后位置对抖振起始迎角影响不大,但对抖振响应强度有明显影响;5边条涡破裂是诱发边条翼布局双垂尾抖振的主要原因。

Twin-vertical-tailed configuration with Leading-Edge Extension （LEX） is the primary configuration of the new generation fighter. However, this configuration could experience vertical fin buffet which is one of the critical technique of the aircraft design. A wind tunnel investigation of buffet on the vertical fin of a twin-vertical-tailed configuration with LEX was conducted in the low speed wind tunnel at Northwestern Polytechnical University. The model was tested over an angle-of-attack range of 0- 50 degree. The buffet response of a configuration with the vertical fin moving forward by 30 mm （which is 15. 8% of the vertical fin mean aerodynamic chord） was also studied for comparison and analysis. The time-response of root bending moment and tip acceleration was presented, along with the power spectra density （PSD） distribution. The Root-Mean-Square （RMS） bending moment and RMS acceleration were also discussed. Results show that： （1） the buffet response occurs in the first bending mode; （2） both the root bending moment and tip acceleration response increase sharply when the angle of attack is higher than 20 degree; （3） the buffet response reaches a maximum in the angle of attack range from 27 to 40 degree; （4） the forward and backward location of the vertical fin has little influence on the buffet onset angle, but has remarkable influence on the buffet response intensity; （5） the bursting of the vortex shed from LEX is the primary contributor to the buffet.