The stability analysis of tri-hybrid nanofluid is examined theoretically in the presence of three types of gravity modulation. Normal mode techniques have been carried out for linear stability analysis, and the truncated Fourier series method is used for non-linear analysis. We observe both stationary and oscillatory convection is possible in the bottom-heavy case, and the onset of convection gets delayed in stationary in comparison to oscillatory. We also observe the onset of convection is earlier in the case of top-heavy with respect to bottom-heavy. Heat and mass transport start earlier in the day–night profile in comparison to other profiles of gravity modulation. In the graph of nusselt number, mass transfer of the first particle increases with an increase in Rn1 value while other two concentration Rayleigh numbers (Rn2, Rn3) does not have any effect on first concentration nusselt number. If we generalize the problem for n-different types of nanoparticles, then two cases may be possible (1) Top-heavy-ordinary nanofluids will be the most stabilizing case. (2) Bottom-heavy-nanofluids with n-type particles will be the most stabilizing case. The most stabilizing case is possible with the same ratio of Rn in the top-heavy, whereas the opposite result is found in the bottom-heavy.

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In this research article, the combined effect of electric field and variable viscosity on the stability of dielectric nanofluid (CuO + water) within a Hele–Shaw cell is studied. The normal mode technique has been implemented for linear stability analysis and the truncated Fourier series method for nonlinear stability analysis. The effect of the Hele–Shaw number, thermorheological parameter, and alternating current electric Rayleigh number on the onset of convection and heat/mass transfer has been investigated analytically, graphically, and using tables. It is observed that the effect of the thermorheological parameter has a destabilizing effect, and the value of the parameter is always less than [Formula: see text] for this study. We also found that the Hele–Shaw number has stabilizing effect, and it is always greater or equal to [Formula: see text] for this study. The effect of alternating current electric Rayleigh number is destabilized. We observed that in the whole analysis, numerical results are better than analytical results.

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