[...]introducing constitutive relations for the fields F of the form F=f(ρ, D, grad T=g, T) for F∈(ε, ψ, η, σE, p ,q), where ψ=ε−Tη is the Helmholtz free energy and σ=σE− p1, in which σEis the extra-stress and p the pressure, it is straightforward to show that Equation (4) takes the form below. −ρ{−∂ψ∂ρρ−pρ}div v+{∂ψ∂T+η}T˙+∂ψ∂D·D˙+∂ψ∂g·g˙+σE·D−q.g...

Phenomenological Thermodynamics of Irreversible Processes

10.3390/e20060479