边条翼布局双垂尾抖振表面脉动压力风洞实验研究

Wind-tunnel unsteady pressure measurements of twin-vertical tail during buffet of strake-wing configuration

对边条翼布局双垂尾发生抖振时的表面脉动压力进行了风洞实验研究。实验在西北工业大学NF-3风洞进行。实验迎角范围：10°-40°，风速：50m／s。实验测量了垂尾内外侧表面各9处的脉动压力，并将脉动压力沿表面积分近似得到垂尾的根部弯矩响应。实验同时测量了垂尾根部应变、翼尖前缘及后缘的加速度响应。实验结果表明，通过不同测量方法得出的垂尾抖振响应规律一致，得到的垂尾抖振起始迎角相同，这表明垂尾的抖振响应是由边条涡破裂流作用在垂尾表面的脉动载荷引起的；随迎角增大，边条涡破裂流的能量不断增加，且越来越集中于低频范围，但当迎角过大时，边条涡的破裂点远离垂尾，破裂涡的能量耗散很大，从而作用在垂尾表面的脉动载荷减弱。

An intensive wind-tunnel investigation of twin-vertical tail buffeting of strake-wing configuration was conducted in the NF-3 wind tunnel at Northwestern Polytechnical University. The test angles-of-attack were about 10° to 40°, and test wind speed was 50m/s. Unsteady pressures at 9 positions on both sides of the vertical tall were recorded, and these unsteady pressures were integrated along the surface to yield the root bending moment of the vertical tail. The root mean square （RMS） value of the unsteady pressures and root bending moment were discussed, along with the power spectra density （PSD） distribution of root bending moment. The RMS value of root bending strain and the tip accelerations at both leading edge and trailing edge were also discussed. Results show that： The trend of the RMS pressures, RMS root bending moment and RMS acceleration are consistent with each other. The unsteady load of vortex breakdown flow impinging on the vertical tail is the primary contributor of the vertical tail buffet. As the angle of attack increases, the energy of vortex breakdown flow enhances, and the peak on the PSD shifts toward the lower frequency. When the vortex breakdown point moves toward upstream and far away from the vertical tail, the energy of breakdown flow is dispersed and the unsteady loads on the vertical tail decrease.