Comparison of the effects of three types of time-periodic body force on linear and non-linear stability of convection in nanoliquids

Abstract

Abstract The effect of three different types of time-periodic vertical oscillations of the Rayleigh–Benard system involving Newtonian nanoliquids is studied in the paper. Twenty nanoliquids are considered for investigation and it is found that enhanced heat transport is seen in all of them compared to what is observed in the corresponding carrier liquids without the nanoparticles. The increase in the amplitude of the vertical vibration is shown to augment convection in the nanoliquids whereas increase in frequency is to inhibit convection. On comparing the extent of heat transport in the presence of modulation with that in its absence, it was found that heat transport diminished in the former case. It was also found that the trigonometric sine type of gravity modulation transports heat intermediate to that of triangular and square types. The triangular type inhibits heat transport while square type enhances heat transport leading one to conclude that heat transport in a Rayleigh–Benard system can be enhanced by using a combination of dilute concentration of nanoparticles and gravity modulation using a square wave.