一种改进型松耦合方法在机翼摇滚计算中的应用

A modified loosely-coupled algorithm for calculation of wing rock

提出了一种简单实用的松耦合机翼摇滚计算方法,该方法采用隐式和显式公式相结合来计算刚体动力学方程并升级网格,使计算结果的收敛性和稳定性随时间步长的增大更好,可以在较大的时间步长下得到合理的计算结果。该方法是在隐式和显式的松耦合方法基础上得到的,通过分析机翼摇滚计算中松耦合方法时间精度低的原因,发现如果基于隐式方法计算角速度和角度,由于计算力矩时网格位置滞后,导致气动力相对于运动滞后,时间步长较大时计算的机翼摇滚振幅偏大;而如果基于显式方法计算角速度和角度,计算力矩时网格位置超前,导致计算的机翼摇滚振幅偏小。通过计算80°后掠三角翼的机翼摇滚,证明了改进型松耦合方法的有效性。

A modified loosely-coupled algorithm is provided for numerical simulation of wing rock. The algorithm combines the explicit and implicit formulas to calculate the dynamics equations and to update girds, improving the temporal convergence and numerical stability, being able to obtain reasonable results with larger time steps. Through analyzing the conventional loosely-coupled algorithm, it is found that if the implicit methods are used to calculate the angular rate and angle, the aerodynamic moments have a large time-lag than motion due to the time-lag of grid. Therefore, the amplitudes of wing rock obtained are larger than experimental values at larger time steps. By contrast, the amplitudes using explicit methods are smaller at larger time steps. By calculating wing rock of swept delta wing being 80°, the feasibility of the modified looselycoupled method is verified.