Accession Number : AD0652594

Title :   INITIAL BEHAVIOR OF THE PSEUDO-SHOCK,

Corporate Author : ILLINOIS UNIV URBANA COORDINATED SCIENCE LAB

Personal Author(s) : Yen,S. M. ; Hicks,B. L.

Report Date : MAY 1967

Pagination or Media Count : 39

Abstract : The behavior of the pseudo-shock at the onset and the early state of relaxation has been studied. The initial relaxation behavior of a gas of elastic spheres has been obtained by solving the Boltzmann equation by Nordsieck's Monte Carlo method for small times (during which less than one molecule in five has collided) with spatially uniform initial velocity distribution function. Calculations are reported for the Mach number M = 1,2,4, and 6. The characteristics of the relaxation of the lateral temperature and the Boltzmann function at the early stage have been compared with those of the large times (during which one molecule has collided up to six times). The initial relaxation of the lateral temperature for M =1, 2 and 4 and for the Bolzmann flux for M = 1 are exponential and the relaxation rate for the lateral temperature seems to be independent of the Mach numbers mentioned. These findings are in agreement with those large times. However, for M =2 and 4, the relaxation. The relaxation of the distribution function has been monitored for twelve chosen velocity bins. In most of the velocity bins, the distribution function seems to relax exponentially for the collision frequency and for two moments of the collision integral at the onset of the relaxation (rho = 0). Comparisons have been made with the corresponding Monte Carlo results to ascertain the accuracy of the latter. (Author)

Descriptors :   (*RELAXATION TIME, GASES), (*TRANSPORT PROPERTIES, GASES), MONTE CARLO METHOD, REACTION KINETICS, DISTRIBUTION FUNCTIONS, ENTROPY, TEMPERATURE

Subject Categories : Physical Chemistry
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE