上仰三角翼的流动与频率特性

Characteristics of Flow and Frequency over Pitching-up Delta Wings

在水洞和风洞中分别完成了上仰三角翼的流动显示和动态测压试验,目的是研究上仰-停止三角翼的流动和频率特性。水洞中的流动显示试验结果表明,在不同的上仰迎角范围和不同的简化频率k值下,三角翼前缘涡破裂点的位置变化是不相同的。通过分析在风洞中测得的三角翼做上仰运动时的压力信号的结果表明,在破裂涡区中,在相同的名义迎角下,无量纲螺旋波的主频比静态时的高,且k值越大无量纲螺旋波频率越高。不同后掠角的三角翼均能得到相似的结论。

Experiments of flow visualization and dynamic unsteady pressure measurement with pitching-up delta wings are carried out in a water channel and a wind tunnel, respectively in order to study the flow and frequency characteristics of the leading-edge vortices over a delta wing undergoing pitching up-stop motions. The re- sult of the flow visualization test shows that in the case of pitching up-stop movement the vortex breakdown position is dependent on the range of incidence at which the wing is subject to pitching up-stop and the re- duced frequency k. Analysis of the pressure signal measured in the wind tunnel shows that when the delta wing is subject to pitching-up, the nondimensional spiral wave frequency at nominal incidence in post-break- down is higher than that at the corresponding static state, and that the larger the k is, the higher the nondimensional spiral wave frequency will be. The same conclusion is obtained with different sweep delta wing configurations.