Accession Number:

AD0614084

Title:

RESEARCH OF AERODYNAMIC METHODS OF PRODUCING ANTENNA WINDOWS IN A PLASMA SHEATH

Descriptive Note:

Scientific rept. no. 1, 14 Oct 1963-19 Oct 1964

Corporate Author:

MITHRAS CAMBRIDGE MA

Personal Author(s):

Report Date:

1964-10-01

Pagination or Media Count:

99.0

Abstract:

Two aerodynamic methods of creating transmission windows in typical plasma sheaths surrounding re-entry vehicles have been investigated 1 the use of jets of coolant from flush nozzles which penetrate across the plasma slab and then mix with the ionized gases as they are carried downstream, 2 the use of a physical flow diverter to bypass some of the ionized flow laterally around the antenna. Equations are developed for the lateral jet penetration in a supersonic stream and for one-dimensional mixing for both perfect gases and real gases in thermodynamic equilibrium. The assumption of real-air equilibrium thermodynamics yields coolant requirements considerably below the perfect gas values for the jet injection method. It is concluded that the jet injection method will reduce a 200 mc. signal attenuation to 3 db. with modest jet flow rates of helium on a typical re-entry trajectory. Conversely, the use of a physical flow diverter is not an effective method of creating a transmission window where the ionization layer is not adjacent to the vehicle surface or where the attenuation needs to be reduced more than 10 db.

Subject Categories:

  • Guided Missile Reentry Vehicles
  • Thermodynamics
  • Aerodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE