Related Experiment Video
Updated: Feb 19, 2026
10:23
Author Spotlight: Computing the Effects of a Local Radiofrequency Hyperthermia Intervention on Tumor Biomechanics
Published on: December 1, 2023
1.0K
Thermal diffusion by Brownian-motion-induced fluid stress
Jennifer Kreft1, Yeng-Long Chen
1Institute of Physics, Academia Sinica, Taipei, Taiwan.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|October 13, 2007
Summary
DNA and spherical particles migrate towards colder areas due to temperature gradients. This thermal migration is driven by thermal-fluctuation-fluid-momentum-flux coupling, with DNA migration matching experimental data.
Area of Science:
- Physics
- Physical Chemistry
- Biophysics
Background:
- The Ludwig-Soret effect describes species migration under temperature gradients.
- The underlying mechanisms of thermal migration remain incompletely understood.
- Previous studies have explored various systems but lacked a unified explanation.
Purpose of the Study:
- To investigate the thermal migration dynamics of DNA and spherical particles.
- To elucidate the role of thermal-fluctuation-fluid-momentum-flux coupling in thermal migration.
- To compare simulation results with experimental observations for DNA thermal diffusion.
Main Methods:
- Utilized a combination of Brownian dynamics and the lattice Boltzmann method.
- Simulated DNA molecules and spherical particles in a thermal gradient.
- Analyzed particle migration and thermal diffusion coefficients.
Main Results:
- Observed DNA molecules migrating to colder regions, consistent with experimental findings.
- Quantitatively validated the thermal diffusion coefficient for DNA against experimental values.
- Found that the thermal diffusion coefficient decreases with increasing spherical particle radius.
- Identified thermal-fluctuation-fluid-momentum-flux coupling as the driver for thermal migration.
Conclusions:
- The study provides a quantitative agreement with experimental DNA thermal migration.
- Demonstrated that particle size influences thermal diffusion.
- Established the crucial role of thermal-fluctuation-fluid-momentum-flux coupling in driving thermal migration in diverse systems.
Related Concept Videos
01:18Newtonian Fluid: Problem Solving
1.0K
Newtonian fluids exhibit a constant viscosity, meaning their shear stress and shear strain rate are directly proportional. This property ensures a predictable and stable response to applied forces, maintaining a linear relationship between force and flow. Examples include water, air, and light oils, consistently demonstrating this proportional behavior regardless of external conditions.
A velocity gradient forms within the fluid when a Newtonian fluid is placed between two parallel plates, with...
A velocity gradient forms within the fluid when a Newtonian fluid is placed between two parallel plates, with...
1.0K
01:28Navier–Stokes Equations
2.4K
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...
2.4K
01:28Euler's Equations of Motion
959
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...
959
01:09Thermal Stress
3.4K
If the temperature of an object is changed while it is prevented from expanding or contracting, the object is subjected to stress. The stress is compressive if the object expands in the absence of constraint and tensile if it contracts. This stress resulting from temperature change is known as thermal stress. It can be quite large and can cause damage. To avoid this stress, engineers may design components so they can expand and contract freely. For instance, on highways, gaps are deliberately...
3.4K
01:11Pressure Variation in a Fluid at Rest
863
In a fluid at rest, the pressure at any point beneath the fluid surface depends solely on the depth, not on the container's shape or size. This principle, known as hydrostatic pressure, arises because, in stationary fluids, there is no acceleration, meaning the forces within the fluid balance out. Only vertical forces, caused by the weight of the fluid above, contribute to pressure changes with depth.
When measuring pressure at two different levels within the fluid, the difference in...
When measuring pressure at two different levels within the fluid, the difference in...
863
01:20Stokes' Law
2.9K
Viscous forces, like friction, are intermolecular forces that resist the relative motion of molecules over each other. When a solid body moves through a liquid, viscous forces drag it in the opposite direction. The force's magnitude depends on the solid's shape and size, as well as its speed and the liquid's coefficient of viscosity, density and temperature.
The expression for the force on a solid spherical object in a fluid is called Stokes' law. Stokes' law is valid only...
The expression for the force on a solid spherical object in a fluid is called Stokes' law. Stokes' law is valid only...
2.9K