Related Experiment Video
Updated: Jun 2, 2026
11:00
Experimental Investigation of Secondary Flow Structures Downstream of a Model Type IV Stent Failure in a 180° Curved Artery Test Section
Published on: July 19, 2016
Regional statistics in confined two-dimensional decaying turbulence
1Theoretical Thermohydraulics Group, MTA KFKI Atomic Energy Research Institute, Budapest H-1525, Hungary.
Summary
Simulations of decaying turbulence reveal that vorticity distributions change with distance from the wall. Regional enstrophy fluctuates, with profiles resembling turbulent channel flows.
Area of Science:
- Fluid Dynamics
- Computational Physics
Background:
- Turbulence simulation is crucial for understanding complex fluid phenomena.
- Decaying turbulence provides a simplified model for studying fundamental turbulent processes.
Purpose of the Study:
- To investigate the behavior of two-dimensional decaying turbulence in a confined square domain.
- To analyze the spatial distribution of vorticity and its statistical properties.
Main Methods:
- Lattice Boltzmann Method (LBM) was employed for numerical simulation.
- Probability Density Functions (PDFs) of vorticity and particle distributions were calculated.
- Analysis was performed across different regions of the simulation domain.
Main Results:
- Regional area-averaged enstrophy exhibits strong temporal fluctuations around a mean after initial decay.
- The ratio of regional to overall enstrophies increases with distance from the wall, mirroring turbulent channel flow velocity profiles.
- Vorticity PDFs are symmetric in the overall domain but become skewed near the boundary layer.
Conclusions:
- The spatial variation of turbulence statistics is significant, particularly near boundaries.
- LBM is effective for simulating complex turbulent flows and their statistical features.
- Observed similarities between enstrophy ratios and velocity profiles suggest universal characteristics in wall-bounded turbulence.
More Related Videos
Related Concept Videos
01:20Region of Convergence of Laplace Tarnsform
The Region of Convergence (ROC) is a fundamental concept in signal processing and system analysis, particularly associated with the Laplace transform. The ROC represents an area in the complex plane where the Laplace transform of a given signal converges, determining the transform's applicability and utility.
Consider a decaying exponential signal that begins at a specific time. When deriving its Laplace transform, the time-domain variable is replaced with a complex variable. This substitution...
Consider a decaying exponential signal that begins at a specific time. When deriving its Laplace transform, the time-domain variable is replaced with a complex variable. This substitution...
01:24Turbulent Flow
Turbulent flow is characterized by unpredictable fluctuations in velocity and pressure, which result in a chaotic fluid movement distinct from the orderly patterns of laminar flow. While laminar flow is governed by smooth, parallel layers with minimal mixing, turbulent flow exhibits highly irregular, three-dimensional patterns. This behavior arises due to instabilities in the fluid's velocity profile, and amplifies as the flow velocity increases. Minor disturbances, known as turbulent spots,...
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...
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,...
01:15Dimensionless Groups in Fluid Mechanics
Dimensionless groups in fluid mechanics provide simplified ratios that help analyze fluid behavior without relying on specific units. The Reynolds number (Re), which represents the ratio of inertial to viscous forces, distinguishes between laminar and turbulent flows, making it essential in the design of pipelines and aerodynamic surfaces. The Froude number (Fr), the ratio of inertial to gravitational forces, is particularly useful in predicting wave formation and hydraulic jumps in...
01:28Irrotational Flow
Irrotational flow is characterized by fluid motion where particles do not rotate around their axes, resulting in zero vorticity. For a flow to be irrotational, the curl of the velocity field must be zero. This imposes specific conditions on velocity gradients. For instance, to maintain zero rotation about the z-axis, the gradient condition: