In this work, the ability of a Reynolds stress model to compute turbulent homogeneous shear flow with significant compressibility effects is discussed. Several studies compressible flows carried out in past years have shown that pressure strain correlation mainly responsible for strong changes magnitude anisotropies. Two recent models term are considered conjunction standard dissipation rate ki...

In this study we have proposed the SIAQR model with time-dependent infection rate. The model’s well-posedness is demonstrated, and then extended to fractional mathematical by employing Caputo-Fabrizio derivative operator. We also used Lipschitz condition linear growth determine conditions under which has a unique solution. numerical solutions are presented. Furthermore, using graphical represen...

Abstract Covid-19 is part of worldwide pandemic since early 2020. Various mathematical models have been proposed to understand the behaviour disease, but most them were failed predict biological phenomenon this infectious diseases they use incorrect assumptions due stage symptoms. The aim paper develop a covid-19 model with nonlinear incidence rate. We some logical assumption model. discretize ...