In order to provide new insights into the energetics of turbulent boundary layer flows with separation, we compute and characterize energy transport lines, which are defined as the lines tangent to the total mechanical energy transport vector field. Separation is induced in a $R{e}_{\theta }=490$ turbulent boundary layer by imposing two types of transpiration velocity profiles at the top boundary of the computational domain: one with suction and blowing, and the other with suction only. For both separation bubbles, we find that energy transport lines can exhibit attractors, which are a manifestation of local dissipation in the flow. We identify several attracting sets along the bottom wall and attracting spiral nodes inside the separation bubbles and their corresponding basins of attraction. The size and positions of the energy basins of attraction help us understand where the available total mechanical energy is transported to due to the mean flow, and turbulent Reynolds and viscous stresses, before it is fully dissipated. The suction-and-blowing separation bubble leads to slightly smaller losses of total mechanical energy than those for a reference non-separated boundary layer, while the suction-only case shows larger losses than the non-separated boundary layer case.

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分离湍流边界层的总机械能传输线和吸引子

为了提供对带有分离的湍流边界层流的能量学的新见解，我们计算并表征了能量传输线，其定义为与总机械能量传输矢量场相切的线。分离是在$\mathrm{[R}{Ë}_{\theta }=490$通过在计算域的顶部边界施加两种类型的蒸腾速度剖面来形成湍流边界层：一种具有吸力和吹气，另一种仅具有吸力。对于这两个分离气泡，我们发现能量传输线可以表现出吸引子，这是流中局部耗散的表现。我们在底壁上确定了几个吸引集，并在分离气泡及其相应的吸引盆中吸引了螺旋结。吸引能池的大小和位置可帮助我们了解在完全耗散之前，由于平均流量，湍流雷诺和粘性应力而将可利​​用的总机械能输送到何处。