Transport Processes in Anisotropic Fluids II. Coupling of Momentum and Energy Transport in a Nematic Mesophase

Abstract

It is a well established fact that transport processes in fluid substances of low molecular weight are adequately described by linear constitutive relations of the formHere, J is the flux of the cntity to be transported and - φ is the driving force—always the gradient of some potential function—for transport of that entity. The parameter k is the conductivity; it depends on the thermodynamic state of the phase in which transport is occurring, but not on the flux or the driving force. Classical examples of Eq. (1) are Fick's law of diffusion, Fourier's law of heat conduction, Ohm's law of electrical conduction, and Newton's law of momentum transport (viscous friction). In the first three cases cited above, a scalar quantity is transported so that J and cfr are vectors; in the last case cited, a vector quantity is transported so that J and φ are tensors of second order.