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Updated: Jun 1, 2026
08:01
The Diffusion of Passive Tracers in Laminar Shear Flow
Published on: May 1, 2018
Passive scalar structures in supersonic turbulence.
1School of Earth and Space Exploration, Arizona State University, P.O. Box 871404, Tempe, Arizona 85287-1404, USA.
Summary
Intermittency in passive scalar structures slightly increases in supersonic turbulent flows, unlike velocity structures. Intense scalar structures remain sheetlike across all Mach numbers, unaffected by shock discontinuities.
Area of Science:
- Fluid dynamics
- Turbulence research
- Supersonic flow phenomena
Background:
- Understanding passive scalar transport is crucial in supersonic turbulent flows.
- Intermittency in turbulent structures affects mixing and energy dissipation.
- Previous studies have not fully characterized scalar intermittency across varying supersonic Mach numbers.
Purpose of the Study:
- To systematically investigate the intermittency of passive scalar structures in supersonic turbulent flows.
- To compare the intermittency of scalar fields with velocity fields.
- To analyze the morphology of intense scalar structures at different supersonic speeds.
Main Methods:
- Conducted a systematic numerical study.
- Analyzed passive scalar and velocity structures.
- Applied the intermittency model of She and Lévêque (1994).
Main Results:
- Scalar structure intermittency increased only slightly from transonic to highly supersonic regimes.
- Velocity structure intermittency increased significantly with Mach number.
- Shocklike discontinuities were absent in the scalar field, explaining the difference.
- Structure functions of the scalar field were well described by the She and Lévêque model.
- Intense scalar structures were consistently sheetlike across all Mach numbers.
Conclusions:
- Scalar intermittency is less sensitive to increasing Mach numbers than velocity intermittency in supersonic flows.
- The sheetlike nature of intense scalar structures is a robust feature.
- The findings provide insights into mixing and structure formation in high-speed turbulent flows.
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