Effect of temperature modulation on magneto double diffusive convection in a fluid layer

The effect of time-dependent temperature gradient on the onset of double diffusive convection in a horizontal layer of electrically conducting fluid has been studied in the presence of an applied vertical magnetic field and a linear stability analysis has been performed. The fluid layer is heated from below and temperature of both the walls has been modulated. The combined effect of the vertical magnetic field and the temperature modulation on double diffusive convection has been investigated using Galerkin method. The value of the critical Rayleigh number is calculated as a function of the frequency and amplitude of modulation, Prandtl number, magnetic Prandtl number, Taylor number, Chandrasekhar number, diffusivity ratio and the solute Rayleigh number. It is found that the effect of magnetic field has a stabilizing influence on the onset of double diffusive convection. Further it is also found that it is possible to advance or delay the onset of convection by proper tuning of the frequency of modulation of the walls' temperature. Stabilizing and destabilizing effects of some other parameters have also been studied.