Experimental Study of Shocked-Plasma Flows with a Double Search-Coil Conductivity Probe

Abstract

Distributions of the electrical conductivity of shock-heated argon plasma flows are studied with a conductivity probe. The device has two search coils in order to correct the boundary-layer effect on the conductivity measurements. The boundary-layer effect is found to be small for the following conditions; initial pressure P1=2 Torr, shock Mach number Ms=14 and 17, and P1=5 Torr, Ms=15. Variation of conductivity agrees with theory. However, it is suggested that this effect may not be negligible for lower values of Ms. An discussion is presented for effect of a disturbed flow due to the presence of the coils inside the shock tube on the conductivity measurements. The boundary-layer thickness is also obtained from the measurements and it agrees with that deduced from the calculated structure by Knöös within the oder of magnitude.