2. Natural internal convection

The concepts developed above are used in this section for situations, encountered in a large number of applications, where natural convection develops inside a duct or in a cavity. First we look at the "chimney" problem (natural convection in a vertical duct), then at convection in cavities. We'll then look at the case of threshold convection in a horizontal layer heated from below (Rayleigh-Bénard problem), followed by two cases of convection in cavities: thermal convection in a cavity whose vertical walls are differentially heated, and thermosolutal convection.