Efficient mixing and combustion in supersonic flow is critical for developing hypersonic airbreathing propulsion systems such as scramjet engines. The short residence time of a few milliseconds of inflow air in a scramjet combustor make it very difficult to achieve efficient and fast fuel/air mixing. In supersonic flow, the compressibility effect suppresses the development of planar free shear layers, which play an important role in low-speed turbulent mixing. For this reason, a mixing strategy based only on planar shear layers cannot be effective, as it requires the use of impractically long engines that result in weight and heat transfer penalties. One of the efficient methods to enhance and accelerate mixing in supersonic flow is to induce streamwise vortices. Because streamwise vortices swirl perpendicular to the airflow, they are less susceptible to compressibility effects and are advantageous for enhancing the mixing process between the injectant and the airflow. Experimental and computational studies on mixing enhancement by streamwise vortices have been extensively conducted over several decades. Therefore, this paper reviews and summarizes research progress on mixing enhancement using streamwise vortices for four widely studied physical devices: lobed mixers, ramp injectors, pylon injectors, and strut injectors. In addition, the mechanisms for generating streamwise vortices, the flow structures of these physical devices, and the effect of streamwise vortices on mixing enhancement are provided.

超音速流中的有效混合和燃烧对于开发超音速吸气推进系统（如超燃冲压发动机）至关重要。超燃冲压发动机燃烧器中几毫秒的流入空气停留时间很短，因此很难实现高效和快速的燃料/空气混合。在超音速流动中，可压缩性效应抑制了平面自由剪切层的发展，这在低速湍流混合中起重要作用。出于这个原因，仅基于平面剪切层的混合策略不能有效，因为它需要使用不切实际的长发动机，这会导致重量和传热损失。在超音速流动中增强和加速混合的有效方法之一是诱导流向涡流。因为流向涡旋垂直于气流，它们不易受压缩效应的影响，有利于增强喷射剂和气流之间的混合过程。几十年来，关于流向涡流混合增强的实验和计算研究已经广泛开展。因此，本文回顾和总结了使用流向涡流对四种广泛研究的物理装置进行混合增强的研究进展：叶状混合器、斜坡喷射器、塔式喷射器和支柱喷射器。此外，还提供了流向涡流的产生机制、这些物理装置的流动结构以及流向涡流对混合增强的影响。几十年来，关于流向涡流混合增强的实验和计算研究已经广泛开展。因此，本文回顾和总结了使用流向涡流对四种广泛研究的物理装置进行混合增强的研究进展：叶状混合器、斜坡喷射器、塔式喷射器和支柱喷射器。此外，还提供了流向涡流的产生机制、这些物理装置的流动结构以及流向涡流对混合增强的影响。几十年来，关于流向涡流混合增强的实验和计算研究已经广泛开展。因此，本文回顾和总结了使用流向涡流对四种广泛研究的物理装置进行混合增强的研究进展：叶状混合器、斜坡喷射器、塔式喷射器和支柱喷射器。此外，还提供了流向涡流的产生机制、这些物理装置的流动结构以及流向涡流对混合增强的影响。