抄録
The problem of the vibrational relaxation of anharmonic oscillators in expansion nozzles has been analysed numerically. It is concluded: (1) Effects of anharmonicity increase with increasing prr*⁄tanθ and/or Tr, where pr and Tr are the reservoir pressure and temperature, and r* and θ are the throat radius and expansion angle of the nozzle respectively. (2) Anharmonicity has the effect of somewhat lowering the translational temperature of gas. This effect being taken into account, the relaxation rate of the vibrational energy gets an increase of less than a factor 1.3 due to anharmonicity. Contrary to the Boltzmann distribution of the harmonic oscillators, however, the vibrational distribution function of the anharmonic oscillators undergoes a considerable distortion in the expanding flow.
