Related Experiment Video
Updated: Sep 1, 2025
09:33
Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases
Published on: July 28, 2013
28.6K
Diffusion tensor imaging of anisotropic inhomogeneous turbulent flow
Amy-Rae P Gauthier1, Noah Stocek1, Benedict Newling1
1UNB MRI Centre, University of New Brunswick, 8 Bailey Drive, Fredericton, New Brunswick E3B 5A3, Canada.
Physical Review. E
|August 17, 2022
Summary
This study introduces a magnetic resonance imaging technique to map turbulence and anisotropy. The eddy diffusion tensor reveals high turbulence and anisotropy in constricted pipe flow.
Area of Science:
- Fluid dynamics
- Biomedical imaging
Background:
- Inhomogeneous anisotropic turbulent flow is prevalent in nature and engineering.
- Measuring such flows accurately presents significant challenges.
Purpose of the Study:
- To introduce a novel magnetic resonance imaging (MRI) technique.
- To spatially map the degree of turbulence and anisotropy in fluid flows.
Main Methods:
- Utilizing diffusion tensor imaging (DTI) principles.
- Applying the eddy diffusion model of turbulence.
- Developing an eddy diffusion tensor represented by a 3x3 matrix.
Main Results:
- The technique successfully maps turbulence magnitude and anisotropy.
- Constricted pipe flow exhibits greatest turbulence magnitude around the jet core.
- The flow demonstrates a high degree of anisotropy.
Conclusions:
- The eddy diffusion tensor provides detailed insights into turbulent fluctuations.
- Correlation time is a crucial factor for interpreting the tensor data.
- The developed MRI technique offers a powerful tool for analyzing complex turbulent flows.
Related Concept Videos
01:07Laminar and Turbulent Flow
9.1K
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...
9.1K
01:24Turbulent Flow
261
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...
261
01:24Magnetic Resonance Imaging
6.2K
Magnetic resonance imaging (MRI) is a noninvasive medical imaging technique based on a phenomenon of nuclear physics discovered in the 1930s, in which matter exposed to magnetic fields and radio waves was found to emit radio signals. In 1970, a physician and researcher named Raymond Damadian noticed that malignant (cancerous) tissue gave off different signals than normal body tissue. He applied for a patent for the first MRI scanning device in clinical use by the early 1980s. The early MRI...
6.2K
01:28Irrotational Flow
543
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:
543
01:17Assessment of Diffusion and Perfusion
1.1K
Understanding and evaluating diffusion and perfusion is critical in assessing a patient's respiratory and circulatory health. These processes play key roles in maintaining the body's internal environment, ensuring that tissues receive adequate oxygen while waste products are efficiently removed.
The Role of Diffusion in Respiration
Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration. In the respiratory system, this...
The Role of Diffusion in Respiration
Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration. In the respiratory system, this...
1.1K
01:28Navier–Stokes Equations
705
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...
705