Abstract
In classical aerodynamics the air is considered as a continuum and its flow characteristics are described by the equations of fluid mechanics. From the standpoint of kinetic theory, the validity of these equations is based on the physical assumption that the behavior of the fluid is determined almost exclusively by the interactions between the individual molecules and only to a very minor, generally negligible, ex tent by the interaction between molecules and solid boundaries. Another expression of this physical situation is contained in the statement that under the conditions encountered in classical fluid mechanics, the mean free paths between individual molecules is very small compared with the dimensions of the bodies in contact with the fluid. If, however, the density of the gas is gradually being decreased to reach such values as, for instance, exist in tne upper atmosphere, the mean free path which is inversely proportional to the density will gradually increase until the condition mentioned above is no longer valid. We are then reaching the regime known as rarefied gas dynamics, which is characterized by a mean free path λ between the molecules of the gas of the same order or even larger than the critical dimension d of the system. The ratio between this mean free path λ and the characteristic dimension K=λ/d, commonly called the Knudsen number, divides gas dynamics into the various flow regimes, values of K<0.01 represent continuum flow, those of K>10 free molecular flow, and intermediate values the re gions commonly called slip and transition flow. In this series of lectures we will be concerned only with the regions of very large K's, that is with free molecular flow, also called Knudsen flow. In this flow regime individual molecules will make many collisions with the solid walls bordering on the system before they will have a chance to collide with one another. As a result, the flow characteristics are determined by the interactions between solid surfaces and gas molecules while the continuum quantities such as viscosity and heat conductivity lose their importance.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
Bibliography
A General References
R.G.J. Fraser, Molecular Rays, Cambridge Univ. Press, 1931
I. Estermann, Molecular Beam Technique, Rev. Mod. Phys. 18, 300,1946
N.F. Ramsey, Molecular Beams, Oxford Univ. Press, 1950
I. Estermann (ed), Recent Research in Molecular Beams, Academic Press, New York, 1959
M. Knudsen, Kinetic Theory of Gases, Methuen, London, 1934 B
Individual Papers
L. Dunoyer, Le Radium, 8,142,1911; 10,400,1913
F.C. Hurlbut, Univ. of Calif. Eng. Proj. Rept HE-150-118, 1953
G. Wessel and H. Lew, Phys.Rev. 92,641,1953
J.B. Taylor, Z.Physik 52, 846, 1929
J.C. Maxwell, On the Dynamic Theory of Gases, Cambridge Univ. Press, Cambridge, 1960
S.A. Schaaf and P.L. Chambré, Flow of Rarefied Gases in High Speed Aerodynamics and Jet Propulsion, Vol. III, Part. H, Princeton Univ. Press, 1958
R.W. Wood, Phil. Mag. 30, 304, 1915
M. Knudsen, Ann.Physik 34, 593, 1911
F. Knauer and O. Stern, Z.Physik 53,779,1929
I. Estermann and O. Stern, Z, Physik 61, 95,1930
A. Ellett and H. Zahl, Phys. Res. 38,977,1931
B. Josephy, Z.Physik 80,733,1933
S. Datz, G.E. Moore and E.H. Taylor, in Rarefied Gas Dynamics, 3rd Symposium, (J. A. Laurmann, ed. ) Vol. I, p. 347 Academic Press, New York, 1963
J.N. Smith and W.L. Fite, ibid, p. 430
I. Estermann, R. Frisch and O. Stern, Z. Physik 73, 348,1931
F.C. Hurlbut and D.E. Beck, Univ. of Calif. Eng. Proj, Rept. HE-150, 166, 1959
R.E. Stickney and F.C. Hurlbut, in Rarefied Gas Dynamics, 3rd Symposium, (J.A.Laurmann, ed ) Vol. I, p. 454, Academic Press, New York, 1963
J.P. Hartnett, in Rarefied Gas Dynamics, 2nd Symposium, (L.Talbot, ed), p.1, Academic Press, New York, 1961
H. Wachman, Ph.D. Thesis, Univ. of Missouri, 1957
A.I. Bennett, Ph.D. Thesis, Carnegie Inst, of Tech. 1953
P.M. Marcus and J.H. McFee, in Recent Research in Molecular Beams (I.Estermann, ed), p.43, Academic Press, New York, 1959; J.H. McFee, Ph.D. Thesis, Carnegie Inst. of Technology, 1959
J.B. Anderson, R.P. Andres, and J.B. Fenn, High Energy and High Intensity Molecular Beams. To appear in Advances in Atomic and Molecular Physics (D.R. Bates and I. Estermann, eds). Vol.I, Academic Press, New York, 1964.
A. Kantrowitz and J. Grey, Rev. Sc. Inst. 22, 328, 1951
E.W. Becker and K. Bier, Zeits.f. Naturforschung 9a, 975,1954
P.B. Moon, Brit. Journ. Appl. Phys;4 97; 1953
I. Amdur, J. Chem. Phys. 11, 157, 1943
F.M. Devienne and J. Souquet, in Rarefied Gas Dynamics (L. Talbot, ed) p. 83, Academic Press, New York, 1961.
Author information
Authors and Affiliations
Editor information
Rights and permissions
Copyright information
© 2011 Springer-Verlag Berlin Heidelberg
About this chapter
Cite this chapter
Estermann, I. (2011). Applications of Molecular Beams to Problems in Rarefied Gas Dynamics. In: Ferrari, C. (eds) Dinamica dei gas rarefatti. C.I.M.E. Summer Schools, vol 33. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-11024-5_5
Download citation
DOI: https://doi.org/10.1007/978-3-642-11024-5_5
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-11023-8
Online ISBN: 978-3-642-11024-5
eBook Packages: Mathematics and StatisticsMathematics and Statistics (R0)