Interfacial Characteristics of Power-Law Viscoelastic Fluid With Heat and Mass Transfer in Planar Configuration

In this study, a linear stability principle is utilized to investigate the Rayleigh–Taylor stability at the power-law viscoelastic fluid/inviscid gas interface. The power-law viscoelastic fluid lies above the gas and heat is transferred from the upper phase to the lower phase and vice versa. The simplified formulation for heat transport derived by Hsieh (1972, “The Effect of Heat and Mass on Rayleigh Taylor Instability,” ASME J. Basic Eng., 94(1), pp. 156–160) is utilized here. In the perturbed state, the mathematical equations are linearized and the well-known normal mode procedure is employed to examine the stability. An implicit dispersion relationship in the terms of growth rate parameter is achieved and solved through the Newton–Raphson method. The various plots are made to study the behavior of flow variables on the stability of the interface. It is found that the instability of the interface decreases if the transfer of heat is increased. The power-law fluid interface is more stable than the inviscid fluid interface while it is more unstable than the corresponding Newtonian fluid interface. The high power-law index makes the system more stable while a denser power-law fluid reduces the interfacial stability. The consistency coefficient and viscosity of power-law fluid both have a stabilizing character.