Derivation of constitutive data for flowing fluids from comparable data for quiescent fluids

► Steady-state constitutive data are shown to furnish comparable unsteady-state data. ► The scheme is effected using linear irreversible thermodynamic principles. ► Calculations do not require knowing the fluid's specific momentum or energy densities. ► The basis of Euler's original model of hydrodynamics is questioned. ► Speculation is proposed as to the form of the correct model.