Taqi A. M. Shatnawi

We focused on developing and analyzing various models for hybrid nanofluid, including the Tiwari–Das, Yamada–Ota, and Xue models. The study investigates the impression of thermal radiation and heat generation on the flow of a water mixture containing single-walled carbon nanotubes (SWCNT) and multi-walled carbon nanotubes (MWCNT) over the permeable vertical stretchable cylinder. The objective is to understand how these models affect boundary layer behavior, thermal performance, and heat transfer enrichment. The use of the governing law of conservation of energy and momentum has been discussed under magnetohydrodynamic (MHD) effects. The equations are converted by means of similarity transformations into ordinary differential equations and then cracked numerically with the bvp4c scheme. A comparative examination calculates model presentation by examining temperature, skin friction, velocity, and heat transfer rates. The results are compared to the literature, validating the proposed models for accuracy and reliability. The Yamada–Ota model exhibited higher temperature and velocity profiles compared to the Xue and Tiwari–Das models of hybrid nanofluid, and the same is also true for the Nusselt number; however, the opposite relationship has been perceived for skin friction.

Thermal analysis is carried out on the flow of Sisko fluid over Riga curved stretching sheet in the presence of Lorentz force and heat energy application. Heat transmission is supported by considering Prescribed Heat Flux (PHF) and Surface temperature (PST). This study explores the role of fluids in solving various bioengineering problems and opportunities for clinical measures to treat blood-related diseases. It has been concluded that medical science requires the Sisko model to be explored in understanding blood transfusion problems. Mathematical modeling yields complex partial differential equations, which are transformed into ordinary differential equations via appropriate transformations. The outcome of these parameters is observed and explored for the best match that suits our defined boundary conditions. Numerical solutions are obtained using the Matlab function bvp4c, setting default tolerance for better approximate solutions. Impacts of associated parameters on various profiles are elaborated with tables and graphs. Temperature (PST) reduces by enrichment in Pr. A higher Prandtl number indicates that temperature disturbances spread more slowly through the fluid. This means that the temperature near the surface takes longer to reach equilibrium with the bulk fluid temperature, leading to a decrease in the surface temperature. The temperature (PHF) become declines by enlarging values of Pr. The Prandtl number determines the ratio of momentum diffusivity to thermal diffusivity. A higher value of Prandtl number indicates lower thermal diffusivity, which can result in a thicker thermal boundary layer.

In this study, we have proposed a mathematical model to describe the dynamics of the spread of Middle East Respiratory Syndrome disease. The model consists of six-coupled ordinary differential equations. The existence of the corona-free equilibrium and endemic equilibrium points has been proved. The threshold condition for which the disease will die out or becomes permanent has been computed. That is the corona-free equilibrium point is locally asymptotically stable whenever the reproduction number is less than unity, and it is globally asymptotically stable (GAS) whenever the reproduction number is greater than unity. Moreover, we have proved that the endemic equilibrium point is GAS whenever the reproduction number is greater than unity. The results of the model analysis have been illustrated by numerical simulations.