非线性伺服气动弹性的时域数值模拟

The numerical simulation of nonlinear aero-servo-elasticity in time domain

运用非定常流场求解器 ,直接求解翼面作任意运动的时域非定常气动力。将拉氏域内的伺服传递函数转化成时域内的伺服状态方程。通过时域气动力、结构状态方程和伺服状态方程的耦合求解 ,实现伺服气动弹性的时域数值模拟。可以方便地模拟如跨音速、大迎角及高超音速等带有不同非线性的伺服气动弹性响应。通过数值模拟发现 ,伺服系统会降低原有气动弹性系统的稳定性 ,结构陷波器的引入可以减弱伺服系统和结构模态的耦合。应用算例给出了大迎角下翼面的极限环响应和 M=7时伺服颤振速度随迎角变化的非线性特性。

By using unsteady aerodynamic solver, the unsteady loads of control surface can be solved directly in time domain. The transfer function of the servo s ystem in Laplace domain is transformed to time domain to produce the servo s tate equations. By solving the time domain aerodynamic equations, structure stat e equations and servo state equations in every time step, the aeroservoelastic p roblem can be simulated in time domain. It can solve the aeroservoelastic proble m with aerodynamic non-linearity easily, such as transonic, high angles of atta c k and hypersonic problem. By numerical simulation, the servo system can greatly reduce the aeroelastic stability. The structural filter added to the system can reduce the coupling effect of servo system and structure mode and increase the c ritical f lutter velocity. We give the examples of the LCO responses at high angle of atta ck and the non-linear characteristic of the aeroservoelastic velocity changing with the increasing angle of attack at Mach number 7.