Abstract This article discusses affordable schlieren methods which can visualize hidden details in three-dimensional high-speed flow. Mainly, two schlieren methods are brought to light, namely inclined schlieren and focusing schlieren. These two methods have been applied to visualize three-dimensional flow fields like normal shock boundary layer interaction in ducts and flows with shock–shock interactions. The paper explains the possibility of measuring normal shock oscillation in spanwise/transverse direction. Shock height variation across the duct span is also illustrated, using inclined schlieren . Scanning of the focusing schlieren setup can give planar views of three-dimensional shock–shock interactions. It is also shown that the two methods can be merged to give the inclined focusing schlieren method which can also be used to understand three-dimensional flow fields. Further, the possibilities and limitations of these flow visualization methods have been discussed. Graphic abstract

中文翻译：

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用于理解三维超声速流动的经济型纹影可视化方法

摘要 本文讨论了可以在三维高速流中可视化隐藏细节的负担得起的纹影方法。主要介绍了两种纹影方法，即倾斜纹影和聚焦纹影。这两种方法已被应用于可视化三维流场，如管道中的正常激波边界层相互作用和具有激波相互作用的流动。该论文解释了在展向/横向测量法向冲击振荡的可能性。还使用倾斜纹影说明了跨管道跨度的冲击高度变化。聚焦纹影装置的扫描可以给出三维冲击-冲击相互作用的平面视图。还表明这两种方法可以合并得到倾斜聚焦纹影方法，该方法也可以用于理解三维流场。此外，还讨论了这些流动可视化方法的可能性和局限性。图形摘要