Abstract
A study is made of the translational relaxation (in the sense of the loss of the original direction of the velocity) of a molecule of mass M injected into the flow field of a light gas (mass of a molecule m). It is shown that when the gas is sufficiently rarefied and M ≫ m the spreading of the wave packet of the heavy particle can mask the mean “classical” deviation of the heavy molecule from the original direction as a result of a collision with a light molecule. Therefore, not all the collisions determined by the gas-kinetic cross section are effective for the observed deflection of the heavy molecule. Some consequences of this behavior of heavy molecules are discussed. The obtained restrictions on classical theory must be taken into account when one is considering problems of the gas dynamics of rarefied mixtures.
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Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 168–171, March–April, 1983.
We thank V. G. Prikhod'ko and A. K. Rebrov for helpful discussions, and E. G. Kolesnichenko for valuable advice.
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Kusner, Y.S., Paklin, B.L. Translational relaxation of a heavy molecule in a light rarefied gas. Fluid Dyn 18, 315–318 (1983). https://doi.org/10.1007/BF01091130
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DOI: https://doi.org/10.1007/BF01091130