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飞行器飞行时受到的非定常气动力是飞行器设计以及机动飞行中须考虑的一个重要因素。采用CFD方法数值模拟了NACA0012翼型在马赫数从0.2~5.0范围变化时做强迫振荡的非定常流场。通过积分法计算了在不同马赫数时翼型的俯仰动导数。计算结果表明,迟滞效应随马赫数的增大先增大后减小,在跨声速区域迟滞效应达到最大;迟滞环的绕向在跨声速区域为顺时针方向;迟滞环顺时针绕向时,动导数大于零,模型动不稳定,逆时针绕向时,动导数小于零,模型动稳定;旋转角速度越大,翼型表面非定常气动效应越明显。
Unsteady aerodynamic forces experienced during flight of an aircraft are an important factor that must be considered in aircraft design and maneuvering. The CFD method is used to numerically simulate the unsteady flow field of NACA0012 airfoil subjected to forced oscillation when Mach number changes from 0.2 to 5.0. The pitch dynamic derivative of the airfoil at different Mach numbers is calculated by integral method. The calculation results show that the hysteresis effect first increases and then decreases with the Mach number increasing, and hysteresis effect reaches the maximum in the transonic region; the hysteresis loop is clockwise in the transonic region; when the hysteresis loop is clockwise, When the dynamic derivative is greater than zero, the dynamic instability of the model and the counter-clockwise direction, the dynamic derivative is less than zero, and the model is stable. The larger the rotational angular velocity is, the more obvious the unsteady aerodynamic effect is.