Accession Number : AD0708512

Title :   UNIFIED MACROSCOPIC THEORY FOR MULTI-PHASE NON-EQUILIBRIUM FLOWS.

Descriptive Note : Annual scientific rept. 15 Nov 68-14 Nov 69,

Corporate Author : NAPLES UNIV (ITALY) ISTITUTO DI AERODINAMICA

Personal Author(s) : Napolitano,Luigi G.

Report Date : DEC 1969

Pagination or Media Count : 98

Abstract : The report presents a general, rigorous, unitary formulation of a macroscopic theory for two-phase non equilibrium flows based on a two-fluid approach. This general theory includes, as particular cases, both the theory of superfluid helium and that of more conventional media in which any number and type of internal and/or external irreversible processes may take place. The theory hinges on a careful rigorous and coherent application of thermodynamics and its main fundamental feature is the reckoning that there are no a-priori reasons for assuming that: (a) the total energy of a composite system in motion can be always separated in a purely kinetic and a purely thermodynamic part; (b) the dissipative fluxes of extensive quantities (i.e. the fluxes contributing to the production of entropy) are necessarily those measured in a frame moving with the c.g. the composite system. The nature and implications of these two assumptions are discussed at length throughout the report, both per se and in relation with other fundamental questions such as, for instance, the characterization of constrained and/or unconstrained equilibria in terms of an energy fundamental relation or of the vanishing of entropy production. Two applications are given. First it is shown how the theory of superfluidity is recovered as a particular case. Secondly a comparison between the classical (one-fluid) and the two-fluid theory is carried out and the approximations inherent to the classical theory are discussed. (Author)

Descriptors :   (*NONEQUILIBRIUM FLOW, *TWO PHASE FLOW), THEORY, HELIUM, LIQUEFIED GASES, SUPERFLUIDITY, IRREVERSIBLE PROCESSES, THERMODYNAMICS, ITALY

Subject Categories : Aerodynamics
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE