吸气条件对圆柱非定常分离流影响的数值研究

A Numerical Simulation of Unsteady Separated Flow Around a Circular Cylinder at Suction Boundary Conditions

本文根据二维可压非定常Ｎ－Ｓ方程，用基于ＢｅａｍａｎｄＷａｒｍｉｎｇ及Ｓｔｅ－ｇｅｒ的方法，在圆柱绕流出现周期性分离后，施加吸气条件，研究吸气对于圆柱非定常绕流的影响。计算结果表明，在恰当的区域施加恰当的吸气条件，可以希望通过减小压差阻力来减小总阻力，吸气还有抑制尾迹中非对称流动的作用，从而使圆柱所受的垂直于来流方向的升力的变化幅度减小，变化频率减小。但是吸气会增加摩擦阻力，过份的吸气会导致摩阻增长太多，从而使得圆柱的总阻力不会减小反而增加。

The unsteady separated flow around a circular cylinder wassimulated numerically at suction boundary conditions after the periodicvortex shedding appearing in the wake.'The computation was based on thework of Beam,Warming and Steger,using two dimensional unsteady com-pressible Navier-Stokes equation. The results are shown which the totaldrag of a circular cylinder can be decreased under some suction condi-tions. Otherwise, the asymmetry in the wake and induced lift can also bealleviated by suction. But it is noted that the suction can lead to in-creasing the friction drag due to flow field changing near the suction wall.So it is necessary for decreasing drag by arranging proper suction intens-ty on proper wall surface area because the possibility of total drag in-creasing may be happened due to stronger suction intensity.