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利用SST k-ω湍流模型对仿生矩形射流表面的减阻特性进行数值模拟,解释了射流表面减小摩擦阻力的原因及对近壁区边界层的控制行为.结果表明,射流孔面积相等时,射流孔与射流表面沿展向长度的比值越大,减阻效果越好.当其它因素不变时,随着射流速度的增大减阻率逐渐增大,随着射流流量的增大减阻率逐渐增大,最大减阻率为35.97%.射流表面对边界层的控制行为表现为主流场近壁区的剪切流动遇到射流的阻抗,在射流孔的背流面形成逆流区,逆流在边界层底层产生的剪应力与主流场方向相反;同时在射流孔下游产生反向旋转涡对并在近壁面诱导出二次涡,相当于在高速流体与壁面之间产生润滑带,使边界层黏性底层厚度增大,速度梯度减小,摩擦阻力减小.
The SST k-ω turbulence model is used to simulate the drag reduction characteristics of the bionic rectangular jet surface, and the reasons of frictional drag reduction on the jet surface and the control behavior of the boundary layer in the near wall are explained. The results show that when the jet hole area is equal, The larger the ratio of jet hole to jet surface length along the span, the better the drag reduction effect.When the other factors are constant, the drag reduction rate increases with the increase of jet velocity and decreases with the jet flow increasing The rate of maximum drag reduction is 35.97% .The control behavior of the jet surface on the boundary layer is as follows: the shear flow in the near wall of the main flow field encounters the jet impedance, the countercurrent zone is formed in the back flow surface of the jet hole, The shear stress generated in the bottom of the boundary layer is opposite to that of the main flow field. At the same time, a counter-rotating vortex pair is generated downstream of the jet hole and a secondary vortex is induced in the near-wall, which is equivalent to generating a lubrication zone between the high-speed fluid and the wall, The thickness of the adhesive layer increases, the velocity gradient decreases, and the frictional resistance decreases.