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建立了适用于双三角翼大迎角非定常分离流场模拟的数值方法,研究双三角翼俯仰振荡时的动态流场特性,给出动态流场结构和气动力性能随迎角的变化规律,重点考察了减缩频率、转轴位置、平均迎角和振幅等参数对动态流场迟滞效应和气动力曲线迟滞环的影响。研究结果表明:俯仰振荡到相同大迎角时上仰和下俯的流场存在明显差异;减缩频率对气动力迟滞效应的影响相对大于转轴位置;平均迎角的变化导致双三角翼背风区流场结构呈现不同流态,而振幅的大小决定这些流态的数目,事实上俯仰运动时如果跨越的流态数目越多则流场结构的动态响应滞后现象就越显著。通过数值分析,有利于提高对双三角翼在俯仰振荡运动条件下的非定常特性和流场滞后效应等非线性现象的认识。
A numerical method suitable for simulating the unsteady flow field at high angle-of-attack of the double delta wing is established. The dynamic flow field characteristics of the twin delta wing during pitching oscillation are studied. The variation of dynamic flow field structure and aerodynamic performance with the attack angle is given. The effect of parameters such as reduction frequency, shaft position, average angle of attack and amplitude on hysteresis loop in dynamic flow field and aerodynamic force curve was investigated. The results show that there is a significant difference between upward tilt and downward tilt when the pitching oscillates to the same angle of attack. The effect of reduction frequency on the aerodynamic hysteresis is relatively greater than that of the shaft. The change of average angle of attack The field structure presents different flow regimes, and the magnitude of the amplitude determines the number of these regimes. In fact, the greater the number of regimes flown during pitching, the more significant is the dynamic response lag of the flow regime. Through numerical analysis, it is helpful to improve the understanding of non-linear phenomena such as unsteady characteristics and hysteresis of flow field in the double delta wing.