细长旋成体大迎角非定常运动数值研究

利用DES方法对处于非对称流态下的细长旋成体进行了俯仰和偏航振荡的数值模拟,观察细长体气动特性尤其是背风面非对称分离涡的变化。计算结果表明在大迎角非对称多涡系情况下,固定频率和振幅的非定常运动可以改变流场结构和气动力,对细长体背风面流态有巨大的影响。俯仰振荡对非对称分离涡有明显的控制作用,抑制流场的非对称性,使分离涡趋于对称;而固定频率的偏航振荡则破坏背风面分离涡的稳定性,激励非对称背涡产生随时间变化的周期性脱落。所进行的非定常运动与细长体流场耦合作用研究在国内外研究尚少。

Numerical Simulation on Unsteady Motion of Slender Body at High Angle of Attack

RANS/LES hybrid methods based on S-A model is presented here to simulate the asymmetric separated flow of the slender under the influence of pitching and yawing oscillation at typical starting angles of attack.It is found that,in multi-asymmetric vortices system flow at high angle of attack,the non-steady motion has very significant influence on the flow field and aerodynamic force around slender body.The pitching oscillation has strong control ability to separated flow,the asymmetrical flow were restrained and tend to symmetry;while for the yawing oscillation affect the structural stability of separated flow,the asymmetrical vortexes was energized and periodic shedding on the cross section over time.The study of coupling effects between the asymmetric flow separation and non-steady motion of slender body is rarely touched at home and abroad.