10 Real-Life Examples of Viscosity
Viscosity is a fluid's resistance to deformation. For a Newtonian fluid, the shear stress τ = μ (du/dy), with μ the dynamic viscosity. Water at 20°C: μ ≈ 1.0 mPa·s; honey ~10 Pa·s; pitch ~2×108 Pa·s.
- Pouring honey vs water. Honey's μ is ~10000× that of water at room temperature.
- Engine oil viscosity grades (SAE 5W–30). Two-number rating gives cold-start and operating-temperature viscosities.
- Blood circulation. Non-Newtonian: apparent μ depends on shear rate and hematocrit.
- Ketchup yield stress. A Bingham plastic: nothing flows until shear exceeds the yield stress.
- Drag on a swimmer. Viscous boundary layer along the body wastes energy.
- Air drag on aircraft. Viscosity sets the skin-friction component of drag.
- Pitch drop experiment (Univ. Queensland). 9 drops in ~100 years; one of the longest-running experiments in physics.
- Lava flow. Basalt at 1200°C has μ ~10–1000 Pa·s; viscosity controls flow speed and shape.
- Lubricants in bearings. Hydrodynamic lubrication keeps surfaces separated by a viscous film.
- Ferrofluid spikes. A magnetorheological fluid's effective viscosity rises with magnetic field, used in dampers and seals.
Recent research on this topic from arXiv
Preprints and papers indexed on arXiv.org. Links open the public abstract pages.
- Viscosity models for silicate melts
Jesper deClaville Christiansen · 2003 ·arXiv:0306460v2
Rheology of silicates (melts or super cooled as glasses) is one of the most important fields to mankind, as geological activity largely influences life. In this paper, unifying empirical models for the Non-Newtonian shear viscosity and the... - Viscosity's impact on nutrient uptake along the gut
Fabian Karl Henn, Karen Alim · 2025 ·arXiv:2504.19235v1
Through switching contraction patterns driving digestive flows, the small intestine balances nutrient uptake and waste removal. Complex segmentation contraction patterns are associated with higher nutrient uptake, while peristaltic contract... - Effects of Newtonian viscosity and relaxation on linear viscoelastic wave propagation
Andrzej Hanyga · 2019 ·arXiv:1903.03814v8
In an important class of linear viscoelastic media the stress is the superposition of a Newtonian term and a stress relaxation term. It is assumed that the creep compliance is a Bernstein class function, which entails that the relaxation fu... - Non-Newtonian corrections to radiative viscosity: Israel-Stewart theory as a viscosity limiter
Lorenzo Gavassino · 2024 ·arXiv:2411.12929v2
Radiation is a universal friction-increasing agent. When two fluid layers are in relative motion, the inevitable exchange of radiation between such layers gives rise to an effective force, which tries to prevent the layers from sliding. Thi...
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