On Triply Diffusive Convection Analogous to Stern Type with Variable Viscosity

The paper mathematically establishes that triply diffusive convection (analogous to Stern type), with variable viscosity and with one of the components as heat, cannot manifest itself as oscillatory motions of growing amplitude in an initially bottom heavy configuration if the thermal Rayleigh number |R|, the Lewis number τ₂ for the second concentration component , μ_min (the minimum value of viscosity μ in the closed interval [0,1]) and the Prandtl number σ satisfy the inequality |R| ≤ 27π⁴/4 τ₂(μ_min + 1/σ) provided D²μ is positive everywhere. It is further proved that this result is uniformly valid for the quite general nature of the bounding surfaces.