Transition from steady to chaotic flow of natural convection on a section-triangular roof

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Haoyu Zhai ◽  
Juan F. Torres ◽  
Yongling Zhao ◽  
Feng Xu
Keyword(s):  
Natural Convection ◽  
Chaotic Flow

scholarly journals Numerical Analysis of General Trends in Single-Phase Natural Circulation in a 2D-Annular Loop

2008 ◽  
Vol 2008 ◽  
pp. 1-10 ◽  
Author(s):  
Gilles Desrayaud ◽  
Alberto Fichera
Keyword(s):  
Natural Convection ◽  
Numerical Analysis ◽  
Single Phase ◽  
Closed Loop ◽  
Dynamic Properties ◽  
Natural Circulation ◽  
Flow Behavior ◽  
Pitchfork Bifurcation ◽  
Chaotic Flow ◽  
Over The Top

The aim of this paper is to address fluid flow behavior of natural circulation in a 2D-annular loop filled with water. A two-dimensional, numerical analysis of natural convection in a 2D-annular closed-loop thermosyphon has been performed for various radius ratios from 1.2 to 2.0, the loop being heated at a constant flux over the bottom half and cooled at a constant temperature over the top half. It has been numerically shown that natural convection in a 2D-annular closed-loop thermosyphon is capable of showing pseudoconductive regime at pitchfork bifurcation, stationary convective regimes without and with recirculating regions occurring at the entrance of the exchangers, oscillatory convection at Hopf bifurcation and Lorenz-like chaotic flow. The complexity of the dynamic properties experimentally encountered in toroidal or rectangular loops is thus also found here.

A 2-D numerical study of chaotic flow in a natural convection loop

2010 ◽  
Vol 53 (1-3) ◽  
pp. 76-84 ◽  
Author(s):  
El Hassan Ridouane ◽  
Christopher M. Danforth ◽  
Darren L. Hitt
Keyword(s):  
Natural Convection ◽  
Numerical Study ◽  
Chaotic Flow

The Effect of Convective Heat Transfer Instabilities on the Diameter of Polymer Optical Fiber

2002 ◽  
Author(s):  
Hayden M. Reeve ◽  
Ann M. Mescher ◽  
Ashley F. Emery
Keyword(s):  
Natural Convection ◽  
Gas Phase ◽  
Fiber Diameter ◽  
Time Dependent ◽  
Polymer Optical Fiber ◽  
Chaotic Flow ◽  
Temperature Oscillations ◽  
Phase Temperature ◽  
Cylindrical Furnace ◽  
Regime Transitions

The effect of various natural convection regimes on the diameter of drawn polymer fiber was studied experimentally. Results indicate that as the buoyant potential of air within a cylindrical furnace enclosure is increased the natural convection regime transitions from laminar to oscillatory, and finally, to chaotic flow. The time-dependent heating caused by the oscillatory and chaotic regimes alters the rheology of the elongating polymer preform, causing detrimental time-dependent variations in the fiber diameter. The gas-phase temperature oscillations recorded on opposite sides of the necking perform were not identically in-phase indicating the convective flow is asymmetric in nature. The period of the recorded oscillations was found to be a function of the driving temperature difference, consistent with prior investigations. Furthermore, near the transition to chaotic flow sub-harmonics were observed within the recorded oscillations. When subjected to oscillatory and chaotic natural convection the standard deviation of the fiber diameter variations was up to 2.5 to 10 times greater, respectively, than that measured under laminar heating conditions. This represents a significant instability mechanism, one that has not been investigated within the context of the fiber drawing process to date.

Chaotic flow in a 2D natural convection loop with heat flux boundaries

2013 ◽  
Vol 61 ◽  
pp. 565-576 ◽  
Author(s):  
William F. Louisos ◽  
Darren L. Hitt ◽  
Christopher M. Danforth
Keyword(s):  
Heat Flux ◽  
Natural Convection ◽  
Chaotic Flow

Natural Convection for Air and Molten Gallium in Square- and Elbow-Shaped Enclosures

2015 ◽  
Vol 789-790 ◽  
pp. 462-470
Author(s):  
Emel Evren-Selamet ◽  
Ahmet Selamet
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Numerical Scheme ◽  
Lead Author ◽  
Convection Flow ◽  
Two Dimensional ◽  
Natural Convection Flow ◽  
Transfer Rates ◽  
Chaotic Flow ◽  
Rayleigh Numbers

Natural convection flow of air and molten gallium in square and elbow-shaped enclosures is studied by a two-dimensional numerical scheme developed by the lead author. The dependence of the flow field and Nusselt number (Nu) on the Rayleigh (Ra) and Prandtl (Pr) numbers is examined in both enclosures. Results are obtained with sufficiently large Rayleigh numbers to observe transition from steady to damped or undamped oscillatory, and chaotic flow. Constant and oscillatory heat transfer rates are compared in both enclosures for air (Pr=0.71) and molten gallium (Pr=0.024).

Natural convection in tilted square cavities with triangular shaped top cold wall

2009 ◽  
Vol 39 (0) ◽  
Author(s):  
Tamanna Sultana ◽  
Sumon Saha ◽  
Goutam Saha ◽  
Md Quamrul Islam
Keyword(s):  
Natural Convection ◽  
Cold Wall
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