In modern gas turbine combustors, flame stabilization is typically achieved by an aerodynamic feature of swirling flows known as vortex breakdown. This phenomenon gives rise to an inner recirculation zone (IRZ) and corresponding inner and outer shear layers. Especially, the inner shear layer is prone to a global hydrodynamic instability known as the precessing vortex core (PVC).¹ The PVC can be described as a single helical-shaped coherent structure (azimuthal wavenumber of unity) which meanders downstream along this shear layer.² The PVC is typically present in isothermal swirling jets. However, in reacting flows, it depends on the density stratification, and thus, the flame shape whether a PVC is present or not.^3–5

中文翻译：

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通过主动流量控制激励旋进涡流核心，以抑制旋流火焰中的热声不稳定性

在现代的燃气轮机燃烧器中，火焰稳定通常是通过涡流的气动特性（称为涡流分解）来实现的。这种现象产生了内部再循环区（IRZ）以及相应的内部和外部剪切层。尤其是，内部剪切层易于发生被称为旋进旋涡芯（PVC）的整体流体动力学不稳定性。¹ PVC可以描述为一个螺旋形的连贯结构（方位角波数为1），沿着该剪切层向下游弯曲。² PVC通常存在于等温旋流喷嘴中。然而，在反应流中，取决于密度分层，并且因此取决于火焰形状是否存在PVC。^3–5