Flow Field Diagnostics in Rarefied Slightly Ionized Hypersonic Flow.

摘要

An experimental investigation was carried out in the hypersonic shock tunnel in which two diagnostic techniques,the cylindrical electrostatic probe and the electron beam density probe,were applied to flow field surveys in rarefied slightly ionized hypersonic flow. Their relative merits have been evaluated. It was found that both can be applied for flow field investigations and particularly,density tracing and mapping,provided that diffusion effects are nonexistent or negligible. In the course of this work,ion and neutral density profiles normal to a sharp flat plate and in the near wake of a 10deg half angle cone were obtained. Also using flush electrostatic probes,the ambipolar diffusion flux of the ionized particles to the plate was measured. A comparison with theoretical results obtained using the Rudman-Rubin formulation for the hypersonic flow about a sharp flat plate modified for slightly ionized flow was carried out. (Author)