Get Fluid with Viscosity and Viscoelasticity

10 Questions

What causes viscous stress in a fluid?

Relative velocity of fluid particles

What does the viscosity tensor map onto the viscous stress tensor?

Velocity gradient tensor

What is the SI unit for viscous stress?

Newton-second per square meter (N·s/m²

What is the measure of a fluid's resistance to flow?

Viscosity

Which type of fluids exhibit different correlations between shear stress and shear rate?

Non-Newtonian fluids

What is the most commonly used unit for dynamic viscosity?

Centipoise (cP

What is the reciprocal of viscosity?

Fluidity

What is the property of materials that react to deformation and rate of deformation?

Viscoelasticity

What is the measure of kinematic viscosity?

Square meters per second (m²/s

What approach is used to calculate viscosity in binary gas mixtures?

Chapman-Enskog approach

Study Notes

Viscous stress in a fluid is caused by relative velocity of fluid particles.
It depends on spatial gradients of flow velocity.
Viscous stresses depend on the first derivatives of velocity.
For Newtonian fluids, this dependence is linear.
Viscosity tensor maps velocity gradient tensor onto viscous stress tensor.
There are 81 viscosity coefficients in total.
The formula for viscous stress can be written in Cartesian coordinates.
The formula involves viscosity tensor and velocity gradient tensor.
The SI units for viscous stress are length squared per time.
Viscous stress is a fundamental concept in fluid mechanics.
Maxwell used the term fugitive elasticity for fluid viscosity.
Some liquids can react like elastic solids when subjected to sudden stress.
Some solids can flow like liquids, albeit very slowly.
Viscoelastic materials possess both elasticity and viscosity.
Viscoelastic solids may exhibit both shear viscosity and bulk viscosity.
The extensional viscosity is a linear combination of the shear and bulk viscosities.
The extensional viscosity describes the reaction of a solid elastic material to elongation.
The extensional viscosity is widely used for characterizing polymers.
Earth materials in geology can also exhibit viscoelastic properties.
Viscoelasticity is a property of materials that react to deformation and rate of deformation.
Viscosity is the measure of a fluid's resistance to flow.
It is measured using viscometers and rheometers.
Non-Newtonian fluids exhibit different correlations between shear stress and shear rate.
Kinematic viscosity is measured in square meters per second (m2/s).
The SI unit of dynamic viscosity is the newton-second per square meter (N·s/m2).
The most commonly used unit for dynamic viscosity is the centipoise (cP).
The reciprocal of viscosity is fluidity, measured in reciprocal poise (P−1, or cm·s·g−1).
Viscosity tends to increase with temperature in gases and decrease with temperature in liquids.
The viscosity of a system depends on how the molecules constituting the system interact.
Viscosity in gases arises principally from the molecular diffusion that transports momentum between layers of flow.
Empirical expressions are the most reliable means of calculating viscosity in liquids.
The same molecular-kinetic picture can be applied to gaseous mixtures.
The viscosity of a binary mixture of gases can be written in terms of individual component viscosities, volume fractions, and intermolecular interactions.
The dependence of viscosity on intermolecular interactions enters through collisional integrals.
The Chapman-Enskog approach is used to calculate viscosity in binary gas mixtures.
The viscosity of a gas mixture is different from that of a single-component gas.
Viscosity is a measure of a fluid's resistance to flow.
Viscosity is affected by factors such as temperature and pressure.
Viscosity can be measured using various instruments such as viscometers.
Viscosity is an important property in many industrial processes.