Non-linear Convection with Time-Periodic Boundary Temperature Effect in Viscoelastic Ferromagnetic Fluids
The present work considers time-periodic-temperature modulation effect on non-linear convection in a viscoelastic ferromagnetic fluids (VFF). For finite amplitude perturbation, minimal representation of Fourier series is used to obtain a non-autonomous system of generalized Khayat-Lorenz model. This model is numerically integrated to determine heat-transfer. The buoyancy and non-buoyancy magnetic parameters, Prandtl number, elastic parameters and modulation parameter effects on heat-transfer are considered. There is reduction in heat-transfer due to temperature modulation. In comparison with stabilizing effect of elastic ratio and modulation amplitude, Deborah number has antagonistic influence. The results pertaining to those of Rivlin-Ericksen, Newtonian and Maxwell fluids are obtained from the present work. Temperature modulation is shown to facilitate sub-critical motions. � 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Modulated gravity effects on nonlinear convection in viscoelastic ferromagnetic fluids between two horizontal parallel plates
In this study, the analysis of nonlinear stability with viscoelastic ferromagnetic fluids as working media is performed by finite-amplitude perturbations. The solution of the resulting nonautonomous system of the Lorenz model (generalized Khayat�Lorenz model of four modes) is obtained numerically to measure the amount of heat transport. The effects of elastic parameters, Prandtl number, modulation parameters, buoyancy magnetic parameter, and nonbuoyancy magnetic parameter on heat transport are studied. Heat transport is quantified through the average Nusselt number, which is determined by solving the scaled Lorenz model. As limiting cases of the study, the results of Newtonian, Maxwell, Rivlin�Ericksen fluids are determined. The results obtained have been presented graphically. � 2021 Wiley Periodicals LLC