CFD方法在小滚转力矩计算上的应用

Application of CFD in Estimation of Small Rolling Moment

计算流体动力学(CFD)方法广泛用于飞行器的设计中,但是涉及气流粘性、分离和激波-边界层相互干扰等方面,一般的CFD计算往往不能令人满意。采用精细的CFD数值方法计算导弹的小滚转力矩,通过两种不同差分格式的计算结果与试验结果的对比,证明了Roe’FDS二阶迎风格式比基于FVS方法的二阶迎风格式的计算结果更好,Roe’FDS格式能更好地分辨气流粘性,模拟气流分离;进而采用Roe’FDS格式计算几种不同电缆罩长鼓包布局的小滚转力矩,寻求最小滚转力矩的导弹外形。结果表明,导弹二、一级只有水平2个电缆罩长鼓包时,其滚转力矩远大于二、一级"+…+"分布4个电缆罩长鼓包的情景,而二、一级4个电缆罩长鼓包"+…×"分布较"+…+"分布可进一步减小滚转力矩。

The Calculating Fluid Dynamics （CFD） has been widely applied to aerocraft designing, while it is not adaptable to the applications involved in viscosity, separation and shock-boundary layer interference of flow fields at all time with ordinary calculation. The elaborate CFD method for rolling moment of missile is introduced. Two results of CFD with different discretization schemes are compared by the results of wind tunnel tests respectively. It is indicated that the Roe＇ FDS scheme could be used to obtain results which are better than using the second-order scheme. The Roe＇ FDS scheme identified viscosity and separation of flow fields better than the second-order scheme. Then, the Roe＇ FDS scheme is adopted to obtain better missile aerodynamic characteristics with smaller rolling moment. The results shows that an arrangement of 4 equally spaced cruciform cable-protrusions compared with 2 equally spaced on 2 stages of missile reduced rolling moment significantly, and interdigitation of 4 cable-protrusions 45° on first stage of missile relative to the second stage produced even more reduction of rolling moment.