Inhomogeneous plane waves in viscous fluids

The propagation of elliptically polarised inhomogeneous plane waves in a linearly viscous fluid is considered. The angular frequency and the slowness vector are both assumed to be complex. Use is made throughout of Gibbs bivectors (complex vectors). It is seen that there are two types of solutions—the zero pressure solution, for which the increment in pressure due to the propagation of the wave is zero, and a universal solution which is independent of the viscosity.Since the waves are attenuated in time, the usual mean energy flux vector is not a suitable way of measuring energy flux. A new energy flux vector, appropriate to these waves is defined, and results relating it with energy dissipation and energy density are obtained. These results are related to a result derived directly from the balance of energy equation.