THE STAGNATION-POINT LANGMUIR PROBE IN A SHOCK TUBE--THEORY AND MEASUREMENTS
HARRY DIAMOND LABS ADELPHI MD
Pagination or Media Count:
A model of the ion-electron flow in the stagnation region between the detached shock and the wall of a Langmuir-type probe is proposed for ionized air in a shock tube at ion mass fractions less than 110,000. Based on the close agreement between numerical calculations and measurements of the probe wall ion current density, the pro posed model gives an accurate description of the ion- electron flow in the stagnation-point boundary layer when negative potentials are applied at the stagnation point of the probe. The procedure is indicated to be applicable also in the region between the detached probe shock and the edge of the boundary layer. The ion and electron densities in the boundary layer are shown to be strongly dependent on the equilibrium conditions for the high- temperature gas behind the shock. Hence, the ion and electron number densities in the undisturbed incident flow ahead of the detached shock cannot be obtained unless it is possible to calculate the changes in the number densities across the shock.
- Fluid Mechanics