Related Experiment Video
Updated: Mar 30, 2026
08:01
The Diffusion of Passive Tracers in Laminar Shear Flow
Published on: May 1, 2018
9.2K
Drift and pseudomomentum in bounded turbulent shear flows
1Department of Mathematics, School of Science, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|November 14, 2015
Summary
This study offers a new interpretation of drift and pseudomomentum in turbulent shear flows. These Lagrangian measures, crucial for understanding fluid dynamics, are analyzed for turbulent channel flow, revealing their behavior across various Reynolds numbers.
Area of Science:
- Fluid Mechanics
- Turbulence Research
- Lagrangian Dynamics
Background:
- Evaluates two Lagrangian measures: drift and pseudomomentum.
- These measures are relevant in rotational, fluctuating shear flows with continuous wave number spectra.
- Previous work expressed these measures using Eulerian space-time correlations, which are difficult to interpret.
Purpose of the Study:
- To express drift and pseudomomentum in a more insightful and interpretable form.
- To analyze the behavior of these measures in turbulent channel flow.
- To investigate the relationship between drift, pseudomomentum, and coherent wall layer structures.
Main Methods:
- Assumed separable space-time correlations (magnitude and spatial diminution).
- Parsed Lagrangian measures into terms involving mean Eulerian velocity and velocity correlations.
- Calculated drift and pseudomomentum for turbulent channel flow across a range of Reynolds numbers.
Main Results:
- Pseudomomentum is negative and linked to turbulence kinetic energy; drift is mixed and influenced by Reynolds stress.
- Both measures approach a terminal form as Reynolds number increases.
- Pseudomomentum shows a single peak; drift is negative near this peak and positive elsewhere, largest near the boundary. Time and velocity scales grow logarithmically.
Conclusions:
- The study provides a clearer understanding of drift and pseudomomentum in turbulent shear flows.
- The findings highlight the intricate link between these Lagrangian measures and coherent wall layer structures.
- The results offer insights into turbulence dynamics and energy transfer mechanisms.
More Related Videos
11:51Visually Based Characterization of the Incipient Particle Motion in Regular Substrates: From Laminar to Turbulent Conditions
Published on: February 22, 2018
9.2K
13:02Three-dimensional Particle Tracking Velocimetry for Turbulence Applications: Case of a Jet Flow
Published on: February 27, 2016
13.2K
Related Concept Videos
01:18Boundary Layer Characteristics
820
When a fluid encounters a solid surface, a boundary layer forms due to the interaction between the fluid's motion and the stationary surface. This phenomenon is characterized by a thin region adjacent to the surface where viscous forces dominate, influencing the fluid's velocity profile. The development of the boundary layer begins at the leading edge of the surface and evolves as the fluid moves downstream.As the fluid flows over the surface, friction between the fluid and the wall slows down...
820
01:07Laminar and Turbulent Flow
11.8K
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...
11.8K
01:22Couette Flow
1.3K
Couette flow represents the flow of fluid between two parallel plates, with one plate fixed and the other moving with a constant velocity. This configuration allows for a simplified analysis using the Navier-Stokes equations, which govern fluid motion under conditions of viscosity and incompressibility. For Couette flow, the assumptions include a steady, laminar, incompressible flow with a zero-pressure gradient in the flow direction. This flow type is beneficial for understanding shear-driven...
1.3K
01:28Navier–Stokes Equations
2.7K
For incompressible Newtonian fluids, where density remains constant, stresses show a linear relationship with the deformation rate, defined by normal and shear stresses. Normal stresses depend on the pressure exerted on the fluid and the rate of deformation in specific directions, which determines how fluid flows under varying pressures. Shear stresses, on the other hand, act tangentially across fluid layers. They explain how adjacent fluid layers slide relative to one another, connecting...
2.7K
01:17Steady, Laminar Flow Between Parallel Plates
1.0K
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.
1.0K
01:28Euler's Equations of Motion
1.1K
In fluid mechanics, shear stresses arise from viscosity, which represents a fluid's internal resistance to deformation. For low-viscosity fluids, like water, these stresses are minimal, simplifying flow analysis by allowing the fluid to be treated as inviscid, or frictionless. In an inviscid fluid, shear stresses are absent, leaving only normal stresses, which act perpendicularly to fluid elements. Notably, pressure — defined as the negative of the normal stress — remains uniform across...
1.1K