飞行器的空间位置、飞行速度、飞行姿态等都是随时间变化的，导致对其飞行过程进行模拟仿真非常困难，在跨声速穿越飞行阶段中面临的问题更加复杂。为探究飞行器在跨声速穿越过程中，时变马赫数效应引起的非定常绕流特性和影响机理，本文以NACA0012翼型为研究对象，采用动态嵌套网格的思想，对飞行器跨声速穿越过程中的时变马赫数效应问题进行数值虚拟飞行仿真，对翼型跨声速穿越飞行过程中的气动特性和压心等的变化规律和机理进行探讨。研究结果表明，跨声速穿越飞行过程中的气动特性非线性变化、气动压心位置的振荡特性与流场激波的位置、激波/附面层干扰、飞行速度与攻角参数等有关。对于定常模拟的穿越过程，升力系数和俯仰力矩系数随马赫数的增加呈现“两升两降”的趋势，随飞行攻角的增加，凹坑区域范围扩大；阻力系数在跨声速区出现阻力发散现象，随着攻角增加，对应的阻力发散马赫数减小；翼型气动压心在亚声速区基本稳定在x/c=0.246的位置，跨声速区的压心位置振荡幅度随攻角增加而减弱；超声速区的气动压心位置基本稳定在x/c=0.454的位置处。在非定常穿越过程中，气动特性的变化趋势与定常穿越非常类似，但跨声速区域的气动特性变化规律和气动压心振荡特性具有明显的加速度迟滞效应。飞行加速度越大，迟滞现象越明显；气动压心位置的振荡幅度随攻角和加速度的增加而减弱。本文研究结论可以为飞行器跨声速飞行控制系统设计、跨声速气弹稳定性和操纵性能评估等相关研究提供借鉴和参考。

The position， speed， as well as the attitude of the aircraft were continuerously in changing with time during the flight， which makes the flight simulation difficult and challenging， and the problems encountered in the flight of acrossing transonic region are more complicated. To explore the unsteady characteristics and influence mechanism caused by the time-varying Mach number effect during the transonic acrossing， the numerical flight simulation of NACA 0012 airfoil acrossing the transonic region was performed with the applications of the dynamic chimera mesh and the time-varing Mach number strategy， focusing on the changing characteristics and the mechanism of aerodynamic characteristics and the pressure center. The simulation results showed that， the nonlinear change of aerodynamic characteristics and the oscillation of the pressure center position were related to the position of the flow shock waves， the shock wave/boundary layer interaction， the flight speed varing and the angle of attack during the transonic acrossing flight. For the transonic acrossing with steady simulation， the curves of lift coefficients and pitching moment coefficients showed the trend of “two rises and two falls” with the increasing of Mach number， and the range of pits area in the curves expands with increase of the flight angle of attack. The drag coefficient diverged when approaching to the transonic region， and the corresponding diverging Mach number decreased with increase of the angle of attack. The airfoil pressure center is basically holding at the position of x/c=0.246 in the subsonic region， while the oscillation of the pressure center position decreased with increase of the angle of attack in the transonic region. and the pressure center position in the supersonic region is finally stable at the position of x/c=0.454. In the process of unsteady transonic acrossing simulation， the trend of aerodynamic characteristics changing is very similar to that of steady transonic acrossing process， but the change of aerodynamic characteristics and pressure center oscillation characteristics showed obviously the hysteresis effects due to the acceleration in the transonic acrossing process. The greater the flight acceleration， the more obvious the hysteresis， and the oscillation amplitude of the pressure center position weakened with increase of the angle of attack， as well as the increase of speed accelerations. The research conducted in the current paper can provide reference for the design of aircraft flight control system， the analysis of transonic aeroelastic stability and the evaluation of flight maneuverability， especially in transonic region.