ABSTRACT
In previous chapters we have discussed the mechanical properties of continuous solid media at constant temperature. In this chapter we shall first discuss the classical, reversible, equilibrium thermodynamics of such a system, in section 3.2. Then in section 3.3 we shall introduce thermal conduction. This can be expected to affect wave motion, on the basis that local compression of the material in the wave may produce heat, some of which may be conducted away from the compressed region irreversibly. The result is that the mechanical energy of the wave may be reduced as the wave propagates through the medium. Thus in section 3.4 we analyse the damping of waves by thermal conduction. While the phenomenon is of basic importance in itself, it is also a good illustration of a wider class of dissipative processes. Our presentation in this chapter largely follows the textbook of Bhatia and Singh (1986). However, as always, further valuable insight can be gained from Landau and Lifshitz (1970), especially section 35, for this topic.
