ON THE NATURE OF THE ENTROPY TRACE IN FLUIDS AND SOLIDS
A. E. Mayer, K. V. Khishchenko
VANT. Ser.: Mat. Mod. Fiz. Proc 2014. Вып.4. С. 3-13.
Physical reasons for the occurrence of the entropy trace at the interface between colliding bodies are analyzed. We show that application of the viscous fluid or elastoplastic solid model provides a physically consistent structure of the entropy trace, which is driven by the processes of dissipation of mechanical energy (viscosity, plasticity). To adequately account for this effect, one should use numerical methods with negligibly small scheme viscosity. Incorporating physical viscosity into the original set of equations of motion makes it possible to obtain a stable solution by a numerical method without artificial or scheme viscosity; by choosing a detailed mesh one can ensure that the numerical solution is stable with an arbitrarily small physical viscosity coefficient. The presence of the physically consistent entropy trace leads us, in particular, to the conclusion that melting of a solid body near the plane of impact begins at smaller impact velocities than melting behind a steady-state shock wave.Keywords: entropy trace, viscous fluid, elastoplastic deformations, melting, numerical method.
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