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Preprint 2009-036

1D compressible flow with temperature dependent transport coefficients

Helge Kristian Jenssen and Trygve K. Karper

Abstract: We establish existence of global-in-time weak solutions to the one dimensional, compressible Navier–Stokes system for a viscous and heat conducting ideal polytropic gas (pressure p=Kθ/τ, internal energy e=cvθ), when the viscosity μ is constant and the heat conductivity κ depends on the temperature θ according to κ(θ)=\bar κ θβ, with 0≤β<3/2. This choice of degenerate transport coefficients is motivated by the kinetic theory of gasses.

Approximate solutions are generated by a semi-discrete finite element scheme. We first formulate sufficient conditions that guarantee convergence to a weak solution. The convergence proof relies on weak compactness and convexity, and it applies to the more general constitutive relations μ(θ)=\bar μ θα, κ(θ)=\bar κ θβ, with α≥0, 0≤β<2 (\bar μ, \bar κ constants). We then verify the sufficient conditions in the case α=0 and 0≤β<3/2. The data are assumed to be without vacuum, mass concentrations, or vanishing temperatures, and the same holds for the weak solutions.

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Helge Kristian Jenssen
Trygve K. Karper
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; 2009-06-25.