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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 17:50 |
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Conference: Bucharest University Faculty of Physics 2023 Meeting
Section: Theoretical Physics and Applied Mathematics
Title:
The evolution of turbulent plumes towards round cross sections and the 'Constructal Law'
Authors:
Cristian-Valer VRACIU (1,2), Andrei MARIN (2)
*
Affiliation:
1) Department of Theoretical Physics, Horia Hulubei National Institute of Physics and Nuclear Engineering, Magurele, Romania
2) Faculty of Physics, University of Bucharest, Bucharest-Magurele, Romania
E-mail
cristian.vraciu@theory.nipne.ro
Keywords:
Constructal Law, Convection, Evolution, Jets/Plumes, Self-similarity
Abstract:
The turbulent buoyant plumes are fundamental turbulent and convective elements that are responsible for the heat transfer by convection in numerous complex systems. Many of these plumes have an elliptic cross section evolving towards a round cross section in the far-field. In this work, we investigate the convective flow of turbulent buoyant plumes with elliptic cross sections to see if the 'Constructal Law' can be used to explain the transition of these plumes to round cross sections. In order to create an energy-consistent plume model for the elliptic turbulent plumes, we take into account the mixing length theory. Using both the numerical and self-similar solutions of our integral model, we investigate how the flow, buoyancy, and entrainment vary on the eccentricity of the plume. In both unstratisfied and unstable situations, we demonstrate that the vertical (longitudinal) flow is optimum for round cross sections, which suggests that the 'Constructal Law' may well be able to explain the transition. Moreover, we examine the entropy production of turbulent plumes with elliptical cross sections, and demonstrate that the development of the plumes to round cross sections cannot be explained by the principal of minimization/maximization of entropy generation.
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