俯仰阻尼导数分量的CFD数值模拟

提出一种直接求解直接阻尼导数的方法,该方法不仅适用于轴对称外形,也适用于非轴对称外形.数值模拟飞行器的非定常强迫沉浮运动和强迫角振动,并在Etkin的非定常气动力模型基础上,辨识得到飞行器的洗流时差导数和俯仰阻尼导数,研究飞行器俯仰通道各阻尼导数的数值计算方法.对弹道外形和基本带翼导弹标模外形及Hyflex升力体外形进行研究分析表明,将阻尼导数分量相加得到的俯仰阻尼导数与直接求解强迫角振动得到的俯仰阻尼导数与试验结果吻合很好,各阻尼导数分量随质心位置的变化趋势也与理论预测相符.对于带翼飞行器,超声速条件下,洗流时差导数在俯仰阻尼导数中占主导作用. 

Numerical simulation of individual components of pitch-damping coefficient sum

An approach for predicting the direct damping derivatives that formed the pitch-damping sum was presented. Application of the technique was made to the axisymmetric projectile configuration as well as the non-axisymmetric winged vehicle. The plunging derivatives and pitch-damping sum were obtained using forced heave and angular motions that excited the different angular rates under the basis of Etkin's unsteady aerodynamic model. The numerical calculation method of pitch damping derivatives was studied. The investigations of HBS and Basic Finner standard model and Hyflex show that the predicted pitch-damping coefficient sum obtained by adding the individually determined coefficients is in excellent agreement with the pitch-damping coefficient sum predicted by forced angular motions and with experimental data, and the variation of the damping derivative components with the location of gravity center is also consistent with the theoretical prediction. As for winged vehicle, the plunging derivative plays a leading role in the pitch-damping coefficient sum in the supersonic region.