Density Disturbance ahead of a Sphere in Rarefied Supersonic Flow

Abstract

An electron‐beam x‐ray technique was used to obtain precise measurements of the density along the stagnation streamline of spherical models tested in a $\text{M\hspace{0.17em}=\hspace{0.17em}4.2}$ (nominal Mach number) nitrogen stream and a $\text{M\hspace{0.17em}=\hspace{0.17em}3.8}$ argon stream. Variation of the total pressure and the model radius provided a Re range (based on free‐stream properties and model radius) of 30‐500 in nitrogen, 100‐2000 in argon. The measurements were made with model surface temperatures of 300° K (equal to the total temperature of the flow) and 78° K.