Characterization of Rayleigh–Taylor Instability at the Fluid–Fluid Interface

Two fluids of different densities superposed one over the other or accelerated toward each other develop instability at the plane interface between the two fluids. This instability known as Rayleigh–Taylor instability (R-T) plays an integral role in fluid atomization, metal liner electromagnetic implosion, inertial confinement fusion, plasma fusion reactors and deuterium–tritium fusion target laser implosion. In the secondary stages of atomization, R-T instability dictates the quality of spray influencing the performance of engines. The objective of this study is to characterize the interfacial instability at the fluid–fluid interface based on growth rate and the wavenumber of the disturbances generated at the interface. The stability of the fluid–fluid interface under the influence of inertial, surface tensional and rotational forces has been investigated. The test fluids taken for this study include standard fluids, namely water and air, forming interfaces with commercially used fluids, namely nitromethane, ethylene glycol, gasoline and diesel. An attempt has been made to understand the factors contributing to instability of the fluid–fluid interface assumed to be inviscid based on the growth rate and critical wavenumber of the generated disturbances.