Abstract: Transient laminar natural convection regimes occurring in a thermal convection loop heated from below and cooled from above are investigated numerically for a wide range of Rayleigh numbers spanning the interval from 10^3 to 2.6 × 10^7. In the model system, the lower half of the loop is heated and maintained at a constant high temperature, while the upper half is cooled and maintained at a constant low temperature. A three-dimensional numerical model based on the finite volume method is used to solve the system of governing flow equations. Simulations are performed using water as the working fluid (Pr = 5.83) and detailed numerical results are presented and discussed for conduction, steady convection, and unsteady flow regimes. Although this subject has attracted researchers for decades, there have been no detailed three-dimensional numerical simulations of the dynamics of flow in the thermal convection loop. The objective of the present study is to fill this gap by presenting the temporal evolution of the velocity and temperature fields at key locations within the system. Emphasis is given to the analysis of dynamical behavior of the flow during the unsteady regime. The complexity of flow in the loop, which is characterized by vertical structures and flow recirculation, is visualized for the first time by performing detailed 3-D numerical simulations.
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Bongard's work focuses on understanding the general nature of cognition, regardless of whether it is found in humans, animals or robots. This unique approach focuses on the role that morphology and evolution plays in cognition. Addressing these questions has taken him into the fields of biology, psychology, engineering and computer science.
Danforth is an applied mathematician interested in modeling a variety of physical, biological, and social phenomenon. He has applied principles of chaos theory to improve weather forecasts as a member of the Mathematics and Climate Research Network, and developed a real-time remote sensor of global happiness using messages from Twitter: the Hedonometer. Danforth co-runs the Computational Story Lab with Peter Dodds, and helps run UVM's reading group on complexity.
Laurent studies the interaction of structure and dynamics. His research involves network theory, statistical physics and nonlinear dynamics along with their applications in epidemiology, ecology, biology, and sociology. Recent projects include comparing complex networks of different nature, the coevolution of human behavior and infectious diseases, understanding the role of forest shape in determining stability of tropical forests, as well as the impact of echo chambers in political discussions.
Hines' work broadly focuses on finding ways to make electric energy more reliable, more affordable, with less environmental impact. Particular topics of interest include understanding the mechanisms by which small problems in the power grid become large blackouts, identifying and mitigating the stresses caused by large amounts of electric vehicle charging, and quantifying the impact of high penetrations of wind/solar on electricity systems.
Bagrow's interests include: Complex Networks (community detection, social modeling and human dynamics, statistical phenomena, graph similarity and isomorphism), Statistical Physics (non-equilibrium methods, phase transitions, percolation, interacting particle systems, spin glasses), and Optimization(glassy techniques such as simulated/quantum annealing, (non-gradient) minimization of noisy objective functions).