Linear stability of confined coaxial jets in the presence of gas velocity oscillations with heat and mass transfer

The linear temporal stability of a confined coaxial jet is studied in the presence of gas velocity oscillations with heat and mass transfer. The viscous potential flow theory is applied to account for the liquid and gas viscosity. Results suggest that gas velocity oscillations have a destabilizing effect when heat and mass transfer is neglected and have a complex effect with heat and mass transfer. The increase and decrease of the forcing frequency are stabilizing and destabilizing factors for low and high values of forcing frequency. Heat and mass transfer has a stabilizing effect for capillary instability and a complex effect for Kelvin-Helmholtz instability without oscillations. Similar results to K-H instability are found when oscillations are considered. Gas viscosity has a destabilizing effect for the cases when heat and mass transfer is neglect or weak. However, gas viscosity has a stabilizing effect with enhanced heat and mass transfer. Moreover, liquid viscosity has a stabilizing effect for all the cases discussed.