![]() For example, honey spreads much slower than water because honey has a higher viscosity than water. It explains the internal friction of a moving fluid. The next layer is in contact with the moving layer since there is internal friction between the two layers, it also accelerates, and so on through the depth of the fluid. A fluid’s (liquid or gas’s) viscosity is its resistance to shape change or movement of adjoining sections relative to one another. The layer of fluid in contact with the moving plate is accelerated and starts to move due to the internal friction between moving plate and the fluid. In the diagram, the fluid is initially at rest. Anyone involved with flow characterization, in research or development, quality. Viscosity measurements are made in conjunction with product quality and efficiency. Brookfield deals with liquids and semi-solids. Fluids have zero shear strength, but the rate at which they are sheared is related to the same geometrical factors A and L as is shear deformation for solids. Viscosity is a principal parameter when any flow measurements of fluids, such as liquids, semi-solids, gases and even solids are made. The motion in the figure is like a continuous shearing motion. Care is taken to ensure that the flow is laminar, that is, the layers do not mix. Each successive layer from the top down exerts a force on the one below it, trying to drag it along, producing a continuous variation in speed from v to 0 as shown. ![]() The layer (or lamina) of fluid in contact with either plate does not move relative to the plate, so the top layer moves at speed v while the bottom layer remains at rest. The bottom plate is held fixed, while the top plate is moved to the right, dragging fluid with it. The fluid to be measured is placed between two parallel plates. ![]() ISSN 0021-9606.\) shows how viscosity is measured for a fluid. "Non‐Newtonian Viscosity of Solutions of Ellipsoidal Particles". Journal of the Physical Society of Japan. "The Effect of the Brownian Motion on the Viscosity of Solutions of Macromolecules, I. The cgs unit of viscosity is poise (P), which has been used in honour of French physiologist Jean Lonard Marie Poiseuille. The SI unit of kinematic viscosity is square metre per second or m 2 /s. American Association for the Advancement of Science (AAAS). The SI unit of viscosity is the pascal second (Pas) or kgm 1 s 1. "Viscosity and the Shape of Protein Molecules". "The Influence of Brownian Movement on the Viscosity of Solutions". Series A, Containing Papers of a Mathematical and Physical Character. ![]() The standard SI unit of viscosity is Newton-second per square meter (. Proceedings of the Royal Society of London. The standard viscosity definition is a fluid's resistance to flow and to deformation through shear stress. "The motion of ellipsoidal particles immersed in a viscous fluid". A practical method for the determination of intrinsic viscosity is with a Ubbelohde viscometer. ![]() In polymer chemistry intrinsic viscosity is related to molar mass through the Mark–Houwink equation. More generally, intrinsic viscosity can be used to assay quaternary structure. For example, the intrinsic viscosity can provide rough estimates of the number of subunits in a protein fiber composed of a helical array of proteins such as tubulin. The intrinsic viscosity is very sensitive to the axial ratio of spheroids, especially of prolate spheroids. The intrinsic viscosity formula may also be generalized to include a frequency dependence. ![]()
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