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Related Experiment Video

Updated: Jul 3, 2026

Experimental Investigation of Secondary Flow Structures Downstream of a Model Type IV Stent Failure in a 180° Curved Artery Test Section

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

Is turbulent mixing a self-convolution process?

Antoine Venaille¹, Joel Sommeria

¹Laboratoire des Ecoulements Géophysiques et Industriels (LEGI) CNRS-UJF-INPG, Coriolis, BP53, Grenoble, France. venaille@coriolis-legi.org

Physical Review Letters

|July 23, 2008

Summary

The evolution of scalar mixing in turbulent flows shows a nonuniversal transition from skewed to Gaussian probability distribution functions (PDFs). This mixing route depends on injector and channel dimensions, impacting PDF evolution models.

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Quantifying Mixing using Magnetic Resonance Imaging

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Last Updated: Jul 3, 2026

Experimental Investigation of Secondary Flow Structures Downstream of a Model Type IV Stent Failure in a 180° Curved Artery Test Section

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Published on: July 19, 2016

Quantifying Mixing using Magnetic Resonance Imaging

Quantifying Mixing using Magnetic Resonance Imaging

Published on: January 25, 2012

Area of Science:

Fluid Dynamics
Turbulence Research
Scalar Transport Phenomena

Background:

Turbulent flows are crucial for mixing processes in various engineering applications.
Understanding the evolution of scalar probability distribution functions (PDFs) is key to predicting mixing efficiency.
Previous models often assumed universal mixing behavior.

Purpose of the Study:

To experimentally investigate the probability distribution function (PDF) evolution of a scalar mixed in a turbulent channel flow.
To determine if the scalar mixing process exhibits universal behavior.
To analyze the influence of geometric parameters on mixing dynamics.

Main Methods:

Experimental measurements of scalar concentration fluctuations.
Analysis of the probability distribution function (PDF) evolution over time.
Varying the ratio of dye injector cross-section to channel cross-section.

Main Results:

The transition of the PDF from a skewed initial state to a Gaussian distribution was observed to be nonuniversal.
The specific pathway to homogenization (a Gaussian PDF) was found to be dependent on the geometric ratio of the injector to the channel.
This nonuniversality challenges existing modeling assumptions.

Conclusions:

Scalar mixing in turbulent channel flows is not a universal process.
Geometric factors, specifically the injector-to-channel cross-section ratio, significantly influence PDF evolution.
The findings necessitate a re-evaluation of PDF evolution models, particularly those based on self-convolution mechanisms, to account for geometric dependencies.