射流表面多因素耦合减阻特性及其对边界层的控制行为

为了研究多因素耦合对射流表面减阻特性的影响,运用可拓学基本原理建立主流场速度、射流速度、射流孔高排布、射流孔底排布等特征耦元及其耦合方式的可拓模型,利用标准k-ε湍流模型对射流表面多因素耦合条件下的减阻特性进行数值模拟,分析射流表面黏性阻力和减阻率减小的原因,以及射流表面多因素耦合对射流孔附近壁面流域边界层的控制行为.结果表明:射流表面多因素耦合的减阻效果较好,最大减阻率为27.69%;多因素耦合条件下的射流表面改变了壁面剪应力分布,影响了边界层的结构,同时,在射流孔下游形成的漩涡改变了边界层的厚度,导致壁面黏性阻力降低,从而使得射流表面具有较好的减阻效果.

Characteristics of Drag Reduction and Control Behavior of Boundary Layer on Multi-Factor Coupling of Jet Surface

In order to study the influence of jet surface under the circumstance of multi factor coupling, an extension module of coupling elements and coupling mode between main flow field velocity and jet velocity, as well as high configuration of jet hole and coupling arrangement of the bottom of the jet hole was built by using the basic principle of extension. The drag reduction characteristics of jet surface under conditions of multi factor coupling were numerically simulated with standard k-ε turbulence model. The reasons for reducing the viscous resistance and drag reduction rate of the jet surface were analyzed, and the controlling behavior of jet surface towards the flow field of the boundary layer of the wall near the jet holes was revealed. The results show that under the condition of multi-factor coupling, the jet surface has a better drag reduction effect, and the best drag reduction rate is 27.69%. The jet surface under conditions of multi-factor coupling changes the shear stress distribution of walls, and affects the structure of boundary layer. Meanwhile, vortexes formed in the downstream of jet holes alter the thickness of boundary layer, which leads to the reduction of viscous resistance near the wall, and makes the jet surface to have the characteristics of drag reduction.