Admasu Abawari | Searcharxiv

arXiv2022

Finite-time thermodynamic process of a two-level quantum heat engine

In this paper, we consider a model of two-level quantum heat engine to investigate the explicit analytic expression for the thermodynamics quantities in different condition under the finite-time operation. In this engine, the working substance is composed of a spin-half particles immersed in a magnetic field. The finite-time thermodynamic processes consisting of two quantum adiabatic and two quantum isothermal processes. This processes working between two heat reservoirs with an inverse temperatures $β_{1}$ and $β_{2}$ ($<β_{1}$). In this processes, we obtain the work, heat, power and efficiency at maximum power output of the model. Our result of the efficiency at maximum power agree with the universal value in the first order of Carnot efficiency.

cond-mat.stat-mech↗

arXiv2021

Computation of Thermodynamic and Hydrodynamic Properties of the Viscous Atmospheric Motion on the Rotating Earth in 2D Using Naiver-Stokes Dynamics

In this article, we model Earth's lower small-scale eddies motion in the atmosphere as a compressible neutral fluid flow on a rotating sphere. To justify the model, we carried out a numerical computation of the thermodynamic and hydrodynamic properties of the viscous atmospheric motion in two dimensions using Naiver-Stokes dynamics, conservation of atmospheric energy, and continuity equation. The dynamics of the atmosphere, governed by a partial differential equation without any approximation , and without considering latitude-dependent acceleration due to gravity. The numerical solution for those governed equations was solved by applying the finite difference method with applying some sort of horizontal air mass density as a perturbation to the atmosphere at a longitude of $5Δλ$ . Based on this initial boundary condition with taking temperature-dependent transport coefficient into account, we obtain the propagation for each atmospheric parameter and presented it graphically as a function of geometrically position and time. All of the parameters oscillating with respect to time and satisfy the characteristics of an atmospheric waves. Finally, the effect of the Coriolis force on resultant velocity was also discussed by plotting contour lines for the resultant velocity for the different magnitude of Coriolis force, then we also obtain an interesting wave phenomena for the respective rotation of the Coriolis force. ~~~~Keywords: Naiver-Stokes Equations; Finite difference method; Viscous atmospheric motion; Viscous dissipation; convective motion.

physics.flu-dyn↗