Non-linear aspects of Görtler instability in boundary layers with pressure gradient
Non-linear aspects of Görtler instability in boundary layers with pressure gradient
复制标题
DOI：
10.1063/1.4972241
复制
发表时间：
2016-12
影响因子：
4.6
通讯作者：
J. K. Rogenski;L. Souza;J. M. Floryan
中科院分区：
文献类型：
--
作者：
J. K. Rogenski;L. Souza;J. M. Floryan
凹表面上的层流可以经历由被称为Gortler涡的纵向涡引发的二次不稳定性驱动的向湍流状态的转变。这些涡通过改变展向和壁面法线方向上的流向速度分量来扭曲边界层结构。数值模拟已经进行了识别的外部压力梯度的发展和饱和的旋涡的作用。结果表明，对于中性压力梯度和有利压力梯度，具有逆压力梯度的流动在饱和位置上游达到饱和。在过渡区，平均展向剪应力比无涡流动中的剪应力大约三倍。
The laminar flow over a concave surface may undergo transition to a turbulent state driven by secondary instabilities initiated by the longitudinal vortices known as Gortler vortices. These vortices distort the boundary layer structure by modifying the streamwise velocity component in both spanwise and wall-normal directions. Numerical simulations have been conducted to identify the role of the external pressure gradients in the development and saturation of the vortices. The results show that flows with adverse pressure gradients reach saturation upstream from the saturation location for neutral and favorable pressure gradients. In the transition region, the mean spanwise shear stress is about three times larger than in the flow without the vortices.