Bow-shock standoff distances over sphere and spherically-blunted cone geometries were examined through experiments in two facilities capable of high-stagnation enthalpy hypersonic flows simulating Mars planetary entry conditions. High-speed and high-resolution schlieren images were obtained in the California Institute of Technology T5 reflected shock tunnel and the Hypervelocity Expansion Tube to examine facility independence of the measurements. Accompanying reacting Navier–Stokes simulations were carried out. A recently developed unified model for sphere and sphere–cone behavior was first verified for high-stagnation enthalpy ${\mathrm{CO}}_2$ flows through simulations with thermal and chemical nonequilibrium. Shock standoff distance measurements in both facilities were found to be in good agreement with model predictions. The need to account for the divergence of the streamlines in conical nozzles was highlighted and an existing model extended to account for changes in shock curvature between parallel and conical flows. The contributions of vibrational and chemical nonequilibrium to the stagnation-line density profile were quantified using the simulation results comparing three chemical kinetic models.

通过在两个能够模拟火星行星进入条件的高停滞焓高超音速流动的设施中进行的实验，研究了球体和球形钝锥体几何形状上的弓形冲击间隔距离。在加州理工学院 T5 反射激波隧道和超高速膨胀管中获得了高速和高分辨率的纹影图像，以检查测量的设施独立性。进行伴随反应的 Navier-Stokes 模拟。最近开发的球体和球体-锥体行为统一模型首先被验证为高停滞焓${\mathrm{二氧化碳}}_2$流通过具有热和化学非平衡的模拟。发现两个设施中的冲击间隔距离测量值与模型预测非常一致。强调需要考虑锥形喷嘴中流线的发散，并扩展了现有模型以考虑平行流和锥形流之间激波曲率的变化。使用比较三种化学动力学模型的模拟结果来量化振动和化学非平衡对停滞线密度剖面的贡献。