Abstract Binary scaling is a similitude law used to study the aerothermodynamics of hypersonic vehicles in ground-based high-enthalpy facilities. It enables the duplication of shock layer flows in the vicinity of the stagnation point, including binary chemistry and nonequilibrium processes, over length scales that are practical for experimental testing. It is built on the assumption of a flow devoid of radiation coupling, which drastically narrows down the envelope of flows for which binary scaling can be used. Indeed, if it is strong enough, radiative heat transfer will cause a substantial amount of energy to leak out of the shock layer to the free-stream and other flow regions. As demonstrated in this paper, the strength of that coupling will increase as the length-scale of the flow increases, impacting other flow properties such as its chemical composition or temperature. The resulting impact on macroscopic features of the flow are for example a reduction of the wall heat flux (both convective and radiative) or of the shock standoff distance. These side impacts are identified with experimental measurements on the shock standoff distance in an expansion tube with CO 2 – N 2 mixture flows representative of the venusian atmosphere over cylinders.

中文翻译：

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辐射耦合对应用于冲击层流的二元标度影响的实验证据

摘要 二元定标是一种用于研究地基高焓设施中高超音速飞行器空气热力学的相似定律。它能够复制驻点附近的冲击层流，包括二元化学和非平衡过程，长度尺度适用于实验测试。它建立在没有辐射耦合的流动的假设之上，这大大缩小了可以使用二进制缩放的流动包络。事实上，如果它足够强，辐射传热将导致大量能量从激波层泄漏到自由流和其他流动区域。正如本文所证明的，这种耦合的强度将随着流动长度尺度的增加而增加，影响其他流动特性，例如其化学成分或温度。对流动的宏观特征产生的影响是例如壁面热通量（对流和辐射）或冲击间隔距离的减少。这些侧面碰撞通过对膨胀管中冲击间隔距离的实验测量来确定，其中 CO 2 – N 2 混合物流代表气缸上方的金星大气。