Investigation of Non-Isothermal Flow in a U-Shaped Tube in the Presence of Natural Convection

Thu, 30 Jul 2026 00:00:00 +0400

Abstract

The article examines the effect of the presence of natural convection on the formation of the thermoelectrokinetic effect in aqueous solutions of ionic compounds. The fields of temperatures and velocities of a liquid located in a U-shaped tube, which is heated from below in the presence of natural and forced convection, are calculated. The model is based on the unsteady Navier --- Stokes equations in the Boussinesq approximation, the thermal conductivity equation, and the continuity condition, supplemented by boundary conditions for forced and natural convection. The solution is obtained using a finite element method with a quadratic approximation of velocity and a linear approximation of pressure and temperature. A numerical analysis of the distribution of temperature and velocity fields at a fixed flow velocity is carried out. The structure of flows in the coils of a U-shaped tube, their spatial localization and quantitative characteristics are determined. The results demonstrate an asymmetric temperature distribution in the tube knees and localization of a sharp temperature gradient in the inlet knee due to the interaction of free and forced convection. The averaged and integral characteristics of the temperature field obtained by numerical calculation are consistent with the experimental results, which indicates the adequacy of the model used. The resulting model will be refined and generalized to simulate thermoelectromagnetic phenomena resulting from self-organization processes caused by natural convection in viscous electrically conductive media

Please cite this article in English as:

Sidorov A.V., Grabov V.M., Zaitsev A.A., et al. Investigation of non-isothermal flow in a U-shaped tube in the presence of natural convection. Herald of the Bauman Moscow State Technical University, Series Natural Sciences, 2026, no. 3 (126), pp. 53--72 (in Russ.). EDN: LDXYRF

Two-Dimensional Janus Alloys for Spintronics on the Example of Fe₂I₃Br₃

Wed, 29 Jul 2026 00:00:00 +0400

Abstract

Two-dimensional (2D) Janus monolayers with mirror asymmetry have exceptional physical properties. This means that they can be used in next-generation optoelectronic, electronic, and electromechanical devices. Thе article presents a first-principles study of the electronic and magnetic properties of the 2D Janus monolayer Fe₂I₃Br₃ using density functional theory. A crystallographic model of the Fe₂I₃Br₃ Janus alloy has been created, its equilibrium structure has been calculated, and its electronic, magnetic, and mechanical properties have been determined. It is shown that the 2D Janus monolayers of Fe₂I₃Br₃ are dynamically and thermodynamically stable, as evidenced by the results of calculations of phonon spectra and formation energies, and also demonstrate a semiconductor nature. The band structure of Fe₂I₃Br₃ has a spin-polarized antiferromagnetic ordering with a band gap of about 1 eV. The Neel temperature was 75 K. In materials of this type, it is possible to realize states that are difficult or practically impossible to obtain in bulk magnetic samples. The results obtained can contribute to the development of science about two-dimensional functional materials, which will find application in various fields of the nanotechnology industry

The results were obtained using the equipment of Shared Resource Center "Far Eastern Computing Resource" IACP FEB RAS (https://www.cc.dvo.ru). The work was supported by the Russian Science Foundation (project no. 25-23-20239)

Please cite this article in English as:

Medintseva T.V., Kartsev A.I., Tarasov Yu.I. Two-dimensional Janus alloys for spintronics on the example of Fe₂I₃Br₃. Herald of the Bauman Moscow State Technical University, Series Natural Sciences, 2026, no. 3 (126), pp. 40--52 (in Russ.). EDN: LMUUFH

Physics. Vestnik MGTU

Investigation of Non-Isothermal Flow in a U-Shaped Tube in the Presence of Natural Convection

Two-Dimensional Janus Alloys for Spintronics on the Example of Fe2I3Br3

Two-Dimensional Janus Alloys for Spintronics on the Example of Fe₂I₃Br₃