Related Experiment Video
Updated: May 26, 2026
07:28
Evolution of Staircase Structures in Diffusive Convection
Published on: September 5, 2018
Thermal nonlinear oscillator in mixed convection
L Martínez-Suástegui1, C Treviño, J C Cajas
1ESIME Azcapotzalco, Instituto Politécnico Nacional, Avenida de las Granjas No. 682, Colonia Santa Catarina, Delegación Azcapotzalco, México, Distrito Federal 02250, Mexico.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|December 21, 2011
Summary
This study simulates transient laminar flow with mixed convection. Varying buoyancy reveals transitions from stationary to periodic and chaotic states in vertical channel flow.
Area of Science:
- Fluid Dynamics
- Heat Transfer
- Nonlinear Dynamics
Background:
- Mixed convection in vertical channels is crucial for thermal management.
- Understanding transient flow behavior under buoyancy effects is complex.
Purpose of the Study:
- To numerically investigate transient laminar mixed convection in a downward vertical channel.
- To analyze the nonlinear dynamical response to buoyancy variations.
Main Methods:
- Solving unsteady 2D Navier-Stokes and energy equations.
- Performing numerical simulations with fixed Reynolds (Re=100) and Prandtl (Pr=7) numbers.
- Varying the Richardson number to study buoyancy effects.
Main Results:
- The system transitions from stationary to periodic (relaxation oscillations) and then chaotic states as buoyancy increases.
- Bifurcations, phase-space plots, and oscillation characteristics were quantitatively analyzed.
- The influence of Reynolds and Prandtl numbers on transitions was examined.
Conclusions:
- Buoyancy significantly alters the flow dynamics, leading to complex nonlinear behaviors.
- The study quantifies transitions in vertical channel mixed convection.
- Results provide insights into the onset of chaos in thermal-fluid systems.
Related Concept Videos
01:17Steady, Laminar Flow Between Parallel Plates
Understanding steady, laminar flow between parallel plates is essential for analyzing and designing flow in narrow rectangular channels, commonly found in various water conveyance and drainage systems. The Navier-Stokes equations govern fluid motion and are generally challenging to solve due to their nonlinearity. However, simplifications are possible in certain cases, like the steady laminar flow between parallel plates. For this scenario, we assume steady, incompressible, laminar flow.
01:28The Thermodynamics of Mixing
Mixing is a fascinating phenomenon in thermodynamics, particularly when considering the Gibbs energy of a mixture at constant temperature and pressure. This energy, denoted as G, tends to decrease during spontaneous mixing processes, offering insights into the composition changes that occur.Imagine two ideal gases, initially separated in different containers, with amounts nA and nB, respectively, both at a temperature T and pressure p. The chemical potentials of these gases have their 'pure'...
01:20Mechanisms of Heat Transfer II
In convection, thermal energy is carried by the large-scale flow of matter. Ocean currents and large-scale atmospheric circulation, which result from the buoyancy of warm air and water, transfer hot air from the tropics toward the poles and cold air from the poles toward the tropics. The Earth’s rotation interacts with those flows, causing the observed eastward flow of air in the temperate zones. Convection dominates heat transfer by air, and the amount of available space for the airflow...
01:14Mechanisms of Heat Transfer I
Just as interesting as the effects of heat transfer on a system are the methods by which the heat transfer occur. Whenever there is a temperature difference, heat transfer occurs. It may occur rapidly, such as through a cooking pan, or slowly, such as through the walls of a picnic ice box. So many processes involve heat transfer that it is hard to imagine a situation where no heat transfer occurs. Yet, every heat transfer takes place by only three methods: conduction, convection, and radiation.
01:23Steady, Laminar Flow in Circular Tubes
Hagen-Poiseuille flow describes a viscous fluid's steady, incompressible flow through a cylindrical tube with a constant radius R. This flow profile is often applied to understand fluid transport in narrow channels, such as capillaries. It serves as a foundational example of laminar flow. In this model, cylindrical coordinates (r,θ,z) are used to describe the radial (r), angular (θ), and axial (z) dimensions within the tube. For Hagen-Poiseuille flow, the velocity profile is purely axial,...
01:07Laminar and Turbulent Flow
Fluid dynamics is the study of fluids in motion. Velocity vectors are often used to illustrate fluid motion in applications like meteorology. For example, wind—the fluid motion of air in the atmosphere—can be represented by vectors indicating the speed and direction of the wind at any given point on a map. Another method for representing fluid motion is a streamline. A streamline represents the path of a small volume of fluid as it flows. When the flow pattern changes with time, the streamlines...