Accession Number : ADA331770

Title :   Shock Waves in Nonequilibrium Gases and Plasmas

Descriptive Note : Doctoral thesis

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH SCHOOL OF ENGINEERING

Personal Author(s) : Hilbun, William M.

PDF Url : ADA331770

Report Date : OCT 1997

Pagination or Media Count : 274

Abstract : An analysis and assessment of three mechanisms describing plasma/shock wave interactions was conducted under conditions typically encountered in a weakly ionized glow discharge. The mechanisms of ion-acoustic wave damping, post-shock energy addition and thermal inhomogeneities were examined by numerically solving the Euler equations with appropriate source terms adapted for each mechanism. Ion-acoustic wave damping was examined by modeling the partially ionized plasma as two fluids in one spatial dimension using the Riemann problem as a basis. Post-shock energy addition in the form of nonequilibrium vibrational energy relaxation was also examined in one spatial dimension using the Riemann problem as a basis. The influence of thermal inhomogeneities on shock wave propagation was examined in two spatial dimensions for both a Riemann shock and a shock generated by a spark discharge. Shocks were propagated through realistic thermal profiles with the resulting shock structure examined through the numerical application of various optical diagnostic techniques. Results from shock simulations indicate that ion-acoustic wave damping has an insignificant effect on the neutral flow at fractional ionization levels typical of glow discharges. Post-shock vibrational energy relaxation is also unable to effect the shock structure on the time scales of interest. An analysis of the effects of thermal inhomogeneities reveals that many of the observed plasma/shock anomalies can be explained based solely on this mechanism.

Descriptors :   *PLASMAS(PHYSICS), *AERONAUTICAL ENGINEERING, SHOCK WAVES, DAMPING, THESES, PARTIAL DIFFERENTIAL EQUATIONS, HETEROGENEITY, NONEQUILIBRIUM FLOW, EULER EQUATIONS, GLOW DISCHARGES.

Subject Categories : Aerodynamics
      Plasma Physics and Magnetohydrodynamics
      Numerical Mathematics

Distribution Statement : APPROVED FOR PUBLIC RELEASE