尖锥强制转捩静/动气动特性数值模拟研究

Numerical study on the static and dynamic aerodynamic characteristics of cones with forced boundary layer transition

  • 摘要: 高速再入飞行器在进入临近空间时,随着雷诺数的增大会发生边界层转捩,改变飞行器的物面压力和摩阻分布,进而影响气动特性和操稳特性。轴对称飞行器由于迎风面和背风面的转捩发生位置不同形成的非对称转捩会产生诱导力和力矩,从而影响飞行器的静/动稳定性。本文基于高速数值模拟软件分析转捩对尖锥的静/动稳定性影响规律,通过给定圆锥壁面转捩位置,在其法向扩展构造出转捩控制面实现了不同形状和位置的强制转捩模拟,强迫俯仰振动下的非定常流场数值模拟和分析结果表明:非对称转捩阵面会影响尖锥气动力/力矩的变化,随着转捩阵面后移,俯仰静稳定性降低,而动稳定性增强;边界层转捩诱导出压力和摩阻增量,在总附加力矩动导数中压力分量占主导。

     

    Abstract: When a high-speed reentry vehicle enters the near space, the boundary layer undergoes the transition process as the Reynolds number increases. The boundary layer transition modifies the surface pressure and skin friction distributions on high-speed vehicles thus affecting the aerodynamic and stability characteristics. For instance, the asymmetric transition fronts on inclined axisymmetric vehicles induce extra force and moment, thereby affecting the vehicle's static and dynamic stability. Consequently, an investigation into the effects of boundary layer transition on aircraft's stability is critical for the design and control of high-speed vehicles. This paper analyzes the influence of boundary layer transition on the static and dynamic stability of a sharp cone using a high-speed numerical simulation software. This is accomplished by conducting numerical simulations of forced transition with different types of transition fronts by integrating RANS models and the forced pitching oscillation method. For this dynamic numerical simulation, a transition control surface is essential, constructed by extending the transition front from the cone surface in the wall-normal direction. Results show that as the transition front moves backward, the static stability decreases while the dynamic stability increases. The boundary layer transition introduces additional pressure and skin friction, with the former being the primary contributor to the overall induced pitching moment dynamic derivative.

     

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