Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Stokes' Law01:20

Stokes' Law

3.5K
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...
3.5K
Accelerating Fluids01:17

Accelerating Fluids

2.5K
When a fluid is in constant acceleration, the pressure and buoyant force equations are modified. Suppose a beaker is placed in an elevator accelerating upward with a constant acceleration, a. In the beaker, assume there is a thin cylinder of height h with an infinitesimal cross-sectional area, ΔS.
The motion of the liquid within this infinitesimal cylinder is considered to obtain the pressure difference. Three vertical forces act on this liquid:
2.5K
Viscosity of Fluid01:19

Viscosity of Fluid

2.3K
Viscosity measures the resistance a fluid offers to flow and deformation. It results from internal friction between layers of fluid moving relative to one another. Dynamic viscosity, denoted by the Greek letter mu (μ), quantifies the force needed to move one fluid layer over another. For Newtonian fluids like water and air, the relationship between the shearing stress and the rate of shearing strain is linear, meaning their viscosity remains constant regardless of the applied stress.
2.3K
Navier–Stokes Equations01:28

Navier–Stokes Equations

2.9K
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...
2.9K
Euler's Equations of Motion01:28

Euler's Equations of Motion

1.2K
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...
1.2K
Thin-Walled Hollow Shafts01:15

Thin-Walled Hollow Shafts

699
In analyzing a thin-walled hollow shaft subjected to torsional loading, a segment with width dx is isolated for examination. Despite its equilibrium state, this segment faces torsional shearing forces at its ends. These forces are quantitatively described by the product of the longitudinal shearing stress on the segment's minor surface and the area of this surface, leading to the concept of shear flow. This shear flow is consistent throughout the structure, indicating a uniform distribution of...
699

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Universal Equilibration Condition for Heavy Quarks.

Physical review letters·2026
Same author

Entanglement Entropy as a Probe beyond the Horizon.

Physical review letters·2025
Same author

Experimental Particle Production in Time-Dependent Spacetimes: A One-Dimensional Scattering Problem.

Physical review letters·2025
Same author

Medium-Enhanced cc[over ¯] Radiation.

Physical review letters·2024
Same author

Quantum field simulator for dynamics in curved spacetime.

Nature·2022
Same author

Discovering Partonic Rescattering in Light Nucleus Collisions.

Physical review letters·2021

Related Experiment Video

Updated: Apr 16, 2026

Experimental Measurement of Settling Velocity of Spherical Particles in Unconfined and Confined Surfactant-based Shear Thinning Viscoelastic Fluids
10:28

Experimental Measurement of Settling Velocity of Spherical Particles in Unconfined and Confined Surfactant-based Shear Thinning Viscoelastic Fluids

Published on: January 3, 2014

15.8K

Accelerating cosmological expansion from shear and bulk viscosity.

Stefan Floerchinger1, Nikolaos Tetradis1,2, Urs Achim Wiedemann1

  • 1Physics Department, Theory Unit, CERN, CH-1211 Genève 23, Switzerland.

Physical Review Letters
|March 21, 2015
PubMed
Summary

Energy dissipation from cosmic fluid perturbations influences cosmic evolution and Einstein

More Related Videos

Studying Large Amplitude Oscillatory Shear Response of Soft Materials
06:07

Studying Large Amplitude Oscillatory Shear Response of Soft Materials

Published on: April 25, 2019

13.9K
Visually Based Characterization of the Incipient Particle Motion in Regular Substrates: From Laminar to Turbulent Conditions
11:51

Visually Based Characterization of the Incipient Particle Motion in Regular Substrates: From Laminar to Turbulent Conditions

Published on: February 22, 2018

9.3K

Related Experiment Videos

Last Updated: Apr 16, 2026

Experimental Measurement of Settling Velocity of Spherical Particles in Unconfined and Confined Surfactant-based Shear Thinning Viscoelastic Fluids
10:28

Experimental Measurement of Settling Velocity of Spherical Particles in Unconfined and Confined Surfactant-based Shear Thinning Viscoelastic Fluids

Published on: January 3, 2014

15.8K
Studying Large Amplitude Oscillatory Shear Response of Soft Materials
06:07

Studying Large Amplitude Oscillatory Shear Response of Soft Materials

Published on: April 25, 2019

13.9K
Visually Based Characterization of the Incipient Particle Motion in Regular Substrates: From Laminar to Turbulent Conditions
11:51

Visually Based Characterization of the Incipient Particle Motion in Regular Substrates: From Laminar to Turbulent Conditions

Published on: February 22, 2018

9.3K

Area of Science:

  • Cosmology
  • Fluid Dynamics
  • General Relativity

Background:

  • Cosmological fluid dynamics are essential for understanding cosmic evolution.
  • Einstein's field equations govern the universe's large-scale structure and dynamics.

Purpose of the Study:

  • To investigate the impact of energy dissipation from local velocity perturbations on cosmic expansion.
  • To analyze the role of dark sector properties and perturbation spectra in this backreaction effect.

Main Methods:

  • Analysis of fluid dynamic fields and their time evolution.
  • Incorporation of shear and bulk viscosity within cosmological models.
  • Examination of perturbation spectra in the dark sector.

Main Results:

  • Energy dissipation significantly affects spatially averaged fluid dynamic fields.
  • The backreaction effect is dependent on viscosity and perturbation properties.
  • Sufficient backreaction could explain the observed accelerated cosmic expansion.

Conclusions:

  • Viscosity and perturbation spectra are key factors in cosmological backreaction.
  • Backreaction offers a potential explanation for cosmic acceleration, alternative to dark energy.