基于雷达散射截面约束的气动优化设计

Aerodynamic optimization with the constrain of radar cross section

采用拉格朗日乘子法优化设计了雷达散射截面约束条件下的锥形融合气动外形。拉格朗日乘子法中的极小化问题采用动态演化的优化设计方法求解。该方法是一种基于非定常演化的优化设计方法,即在求解非定常流动支配方程的时候同时履行优化过程,较其它基于定常解的优化方法具有高得多的计算效率。其中的雷达散射截面通过求解非结构的笛卡儿网格上的时域麦克斯韦方程来得到,而升阻比则通过求解锥形流方程来计算。通过优化设计,得到了M∞=8.0时,升阻比为4.98,雷达散射截面只有1.66m2的锥形融合气动外形。

In this paper, adopting the radar cross section as the constraint condition, a new conical aerodynamic configuration is presented using the Lagrange multiplier method, and the minimization problems are solved by the dynamic evolution method. In the dynamic evolution method, the unconstraint optimization is executed, simultaneously with the unsteady flow governing equations solved and objective function gradient obtained. This method costs less computing spending than other optimal methods based on solving steady state flow governing equations. The RCS of the configuration is computed using Finite-Volume Time-domain （FVTD） Method to solving the Maxwell equations; the lift-to-drng ratio is obtained by solving the conical flow equations. As a result, the optimum conical configuration is achieved, and whose lift-to-drng ratio reaches 4.98, RCS is only 1.66 m^2.