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首先采用二阶ROE格式计算了非定常NS方程下高超声速钝锥体的俯仰阻尼导数,通过与文献中内伏牛顿法和实验结果对比验证了本文所采用非定常计算方法的正确性。同时采用二阶ROE格式及双时间步长、刚性旋转动网格技术等,数值分析了NS方程计算条件下高空高马赫数钝锥体模型的强迫振动非定常流场特征,并运用最小二乘法辨识出其俯仰静稳定性导数与俯仰阻尼导数。通过计算结果对比分析了不同高度(含稀薄气体效应)、Maxwell滑移边界条件及五组元化学非平衡模型对钝锥体模型非定常流动特征及静、动导数的影响。结果分析表明,本文所计算的钝锥模型在所假设强迫振动下的俯仰稳定性参数随高度变化剧烈,且考虑滑移边界条件与化学反应会使得俯仰力矩迟滞曲线形态发生较大程度改变。准确计算高空、高马赫数条件下飞行器俯仰阻尼导数应考虑化学非平衡效应和稀薄气体效应的影响,是否考虑这些物理效应会关系到飞行器静、动稳定的程度。
First of all, the second-order ROE scheme is used to calculate the pitch-dependent damping derivatives of hypersonic dumbbells under unsteady Navier-Stokes equations. The correctness of the unsteady method is validated by comparison with the experimental results in the literature. In the meantime, the unsteady forced flow field characteristics of the high-altitude and high-Mach number blunt conical model under the NS equation are analyzed numerically by using the second-order ROE scheme, the double time step and the rigid rotating grid technique. The least-square method The pitch stability and pitch damping derivatives were identified. The effects of different heights (including lean gas effect), Maxwell slip boundary conditions and five-component chemical unbalance model on the unsteady flow characteristics and the static and dynamic derivatives of the blunt cone model are analyzed and compared. The results show that the pitch stability parameter of the blunt cone model under the assumed forcing vibration changes drastically with height, and the slipping pitch moment hysteresis curve changes to a great extent when considering the slipping boundary conditions and the chemical reaction. Accurately calculating the altitude and high Mach number of aircraft pitch damping derivative should consider the effects of chemical non-equilibrium and lean gas effects, whether to consider these physical effects will be related to the aircraft static and dynamic stability.