Double diffusive natural convection i.e., flows generated by buoyancy
due to simultaneous temperature and concentration gradients,
occurs in different ranges of fields such as oceanography, drying processes,
crystal growth processes, solar desalination, etc. This convection
was largely studied for aiding or opposed temperature and
concentration gradients. Studies on this subject can be found in several
publications [1–16]. It was noted that, for a buoyancy number near
the unity, an oscillatory flow takes place, caused by the interaction
between thermal and compositional cells. Nishumira et al. [13] carried
out a careful description of the mechanism of this oscillatory
flow.