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Constitutive surfaces in fluid mechanics

Published online by Cambridge University Press:  24 October 2008

M. J. Sewell
Affiliation:
University of Reading
D. Porter
Affiliation:
University of Reading

Abstract

The new concept of a constitutive surface is introduced into inviscid fluid mechanics, with special reference to compressible gas dynamics and to shallow water theory. The detailed shape of such surfaces is calculated, including the manner of their transition across singularities where the Mach or Froude number passes through unity. The calculation draws upon recent work describing the transition of a Legendre transformation through its singularity. For example, mass flow Q, total energy h and flow stress P are always related by part of a ‘swallowtail’ surface, regardless of the particular motion.

The addition of dynamical conditions defines particle history tracks which always lie on constitutive surfaces even for unsteady flow, except that they may jump from one part to another of such a surface when shock waves or hydraulic jumps are passed through.

Illustrations given include the steady flow of a general gas through a standing normal shock, general shallow water theory, and flow along a sloping-sided channel. Connections with existing literature are described.

Type
Research Article
Copyright
Copyright © Cambridge Philosophical Society 1980

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References

(1)Benjamin, T. B.A unified theory of conjugate flows. Phil. Trans. Boy. Soc. Lond. A 269 (1971), 587647.Google Scholar
(2)Benjamin, T. B. and Lighthill, M. J.On cnoidal waves and bores. Proc. Boy. Soc. Lond. A 224 (1954), 448460.Google Scholar
(3)Calladine, C. R.A new thermodynamic diagram for representing steady one-dimensional compressible fluid flow. J. Mech. Engng. Sci. 16 (1974), 192195.CrossRefGoogle Scholar
(4)Chadwick, P.Continuum mechanics (Allen and Unwin, London, 1976).Google Scholar
(5)Courant, R. and Friedrichs, K. O.Supersonic flow and shock waves (Interscience, New York, 1948).Google Scholar
(6)Henderson, F. M.Open channel flow (Macmillan, New York, 1966).Google Scholar
(7)Hill, R.New horizons in the mechanics of solids. J. Mech. Phys. Solids 5 (1956), 6674.CrossRefGoogle Scholar
(8)Lighthill, M. J.Waves in fluids (Cambridge University Press, 1978).Google Scholar
(9)Noble, B. and Sewell, M. J.On dual extremum principles in applied mathematics. J. Inst. Maths. Appl. 9 (1972), 123193.CrossRefGoogle Scholar
(10)Sewell, M. J.On reciprocal variational principles for perfect fluids. J. Math. Mech. 12 (1963), 495504.Google Scholar
(11)Sewell, M. J.On the connection between stability and the shape of the equilibrium surface. J. Mech. Phys. Solids 14 (1966), 203230.CrossRefGoogle Scholar
(12)Sewell, M. J.On dual approximation principles and optimization in continuum mechanics. Phil. Trans. Boy. Soc. Lond. A 265 (1969), 319351.Google Scholar
(13)Sewell, M. J. On applications of saddle-shaped and convex generating functionals. In Physical structure in systems theory, ed. van Dixhoorn, J. J. and Evans, F. J., pp. 219245. (Academic Press, London, 1974).Google Scholar
(14)Sewell, M. J.On Legendre transformations and elementary catastrophes. Math. Proc. Cambridge Philos. Soc. 82 (1977), 147163.CrossRefGoogle Scholar
(15)Sewell, M. J. Degenerate duality, catastrophes and saddle functionals. Lectures to the Summer School on Duality and Complementarity in the Mechanics of Solids. Polish Academy of Sciences, Warsaw (1977). To be published in Mechanics today, vol. 6 (Pergamon Press).Google Scholar
(16)Sewell, M. J.On Legendre transformations and umbilic catastrophes. Math. Proc. Cambridge Philos. Soc. 83 (1978), 273288.CrossRefGoogle Scholar
(17)Sewell, M. J.Some global equilibrium surfaces. Int. J. Mech. Engng. Educ. 6 (1978), 163174.Google Scholar
(18)Sewell, M. J. Legendre transformations and extremum principles. To be published in Mechanics of solids: The Rodney Hill 60th Anniversary Volume, ed. Hopkins, H. G. and Sewell, M. J. (Pergamon Press, Oxford, 1981).Google Scholar
(19)Shercliff, J. A.Generalized gas dynamics teaching. Int. J. Mech. Engng. Educ. 5 (1977), 721.Google Scholar
(20)Stoker, J. J.Water waves (Interscience, New York, 1957).Google Scholar
(21)Truesdell, C. and Toupin, R. A. The classical field theories. In Handbuch der Physik, III/l, ed. Flügge, S. (Springer-Verlag, Berlin, 1960), pp. 226858.Google Scholar
(22)Wehausen, J. V. and Laitone, E. V. Surface waves. In Handbuch der Physik, IX/III, ed. Flügge, S. (Springer-Verlag, Berlin, 1960), pp. 446778.Google Scholar
(23)Zeeman, E. C.Catastrophe theory. Selected papers 1972–1977 (Addison-Wesley, Reading, Mass., 1977).Google Scholar