Non-stationary material transport

Abstract

In Sects. 16.1, 16.2 and 16.3 of this chapter we will solve three problems where we can apply the Quasi-Steady State (QSS) approximation, that we have already encountered in Sects. 5.5 and 9.4. This hypothesis is valid when the characteristic time needed to change the boundary conditions is much longer than the time needed to reach steady state. Then, in the last Sect. 16.4, we will see an examples where this assumption is not applicable, showing how much more difficult these problems become.