Newtonian Fluid

Newtonian fluid

A fluid whose stress at each point is linearly proportional to its strain rate at that point. The concept was first deduced by Isaac Newton and is directly analogous to Hooke's law for a solid. All gases are newtonian, as are most common liquids such as water, hydrocarbons, and oils.

A simple example, often used for measuring fluid deformation properties, is the steady one-dimensional flow u(y) between a fixed and a moving wall (see illustration). The no-slip condition at each wall forces the fluid into a uniform shear strain rate ε, given by Eq. (1), (1) which is induced by a uniform shear stress &tgr;. Here V is the speed of the moving wall, H is the perpendicular distance between the walls, and u is the fluid velocity at distance y from the fixed wall.

A fluid sheared between two plates

If the fluid is newtonian, the experimental plot of &tgr; versus will be a straight line. The constant of proportionality is called the viscosity μ of the fluid, as stated in Eq. (2). (2) The viscosity coefficients of common fluids vary by several orders of magnitude. See Fluid flow, Fluids, Viscosity

Newtonian Fluid

a fluid that obeys Newton’s law of viscous friction. For rectilinear laminar flow, this law states that the shear stress τ in the planes of contact of layers of the fluid is directly proportional to the derivative of the rate of flow ν in the direction of the normal n to these planes; that is, τ = η(∂ν/∂n) where η is the coefficient of viscosity. In the general case of a three-dimensional flow, for a Newtonian fluid a linear relation holds between the stress tensor and the tensor of the rates of strain. Most liquids, including water and lubricating oil, and all gases have the properties of a Newtonian fluid. The flow of Newtonian fluids is studied in hydrodynamics and aerodynamics.

Non-Newtonian fluids are fluids for which the relations indicated above are not linear, for example, for the rectilinear flow

where k ≠ 1. Examples are a number of suspensions and solutions of polymers. Rheology is the study of such flows.

S. M. TARG

Newtonian fluid

[′nü′tō·nē·ən ′flü·əd] (fluid mechanics) A simple fluid in which the state of stress at any point is proportional to the time rate of strain at that point; the proportionality factor is the viscosity coefficient.

newtonian fluid

new·to·ni·an flu·id

a fluid in which flow and rate of shear are always proportional to the applied stress; such fluid precisely obeys Poiseuille law. Compare: nonnewtonian fluid.

Newton,

Sir Isaac, English physicist, 1642-1727. newton - derived unit of force in the SI system.Newton disk - a disk on which there are seven colored sectors, which, when rapidly rotated, appear white.Newton law - the attractive force between any two bodies is proportional to the product of their masses and inversely proportional to the square of the distance between their centers. Synonym(s): law of gravitationNewton rings - colored rings on thin surfaces.newtonian aberration - the difference in focus or magnification of an image arising because of a difference in the refraction of different wavelengths composing white light. Synonym(s): chromatic aberrationnewtonian constant of gravitation - a universal constant relating the gravitational force, attracting two masses toward each other when they are separated by a distance.newtonian flow - the type of flow characteristic of a newtonian fluid.newtonian fluid - a fluid in which flow and rate of shear are always proportional to the applied stress.newtonian viscosity - the viscosity characteristics of a newtonian fluid.

单词	newtonian fluid
释义	DictionarySeeSir Isaac Newton Newtonian Fluid Newtonian fluid A fluid whose stress at each point is linearly proportional to its strain rate at that point. The concept was first deduced by Isaac Newton and is directly analogous to Hooke's law for a solid. All gases are newtonian, as are most common liquids such as water, hydrocarbons, and oils. A simple example, often used for measuring fluid deformation properties, is the steady one-dimensional flow u(y) between a fixed and a moving wall (see illustration). The no-slip condition at each wall forces the fluid into a uniform shear strain rate ε, given by Eq. (1), (1) which is induced by a uniform shear stress &tgr;. Here V is the speed of the moving wall, H is the perpendicular distance between the walls, and u is the fluid velocity at distance y from the fixed wall. A fluid sheared between two plates If the fluid is newtonian, the experimental plot of &tgr; versus will be a straight line. The constant of proportionality is called the viscosity μ of the fluid, as stated in Eq. (2). (2) The viscosity coefficients of common fluids vary by several orders of magnitude. See Fluid flow, Fluids, Viscosity Newtonian Fluid a fluid that obeys Newton’s law of viscous friction. For rectilinear laminar flow, this law states that the shear stress τ in the planes of contact of layers of the fluid is directly proportional to the derivative of the rate of flow ν in the direction of the normal n to these planes; that is, τ = η(∂ν/∂n) where η is the coefficient of viscosity. In the general case of a three-dimensional flow, for a Newtonian fluid a linear relation holds between the stress tensor and the tensor of the rates of strain. Most liquids, including water and lubricating oil, and all gases have the properties of a Newtonian fluid. The flow of Newtonian fluids is studied in hydrodynamics and aerodynamics. Non-Newtonian fluids are fluids for which the relations indicated above are not linear, for example, for the rectilinear flow where k ≠ 1. Examples are a number of suspensions and solutions of polymers. Rheology is the study of such flows. S. M. TARG Newtonian fluid [′nü′tō·nē·ən ′flü·əd] (fluid mechanics) A simple fluid in which the state of stress at any point is proportional to the time rate of strain at that point; the proportionality factor is the viscosity coefficient. newtonian fluid new·to·ni·an flu·id a fluid in which flow and rate of shear are always proportional to the applied stress; such fluid precisely obeys Poiseuille law. Compare: nonnewtonian fluid. Newton, Sir Isaac, English physicist, 1642-1727. newton - derived unit of force in the SI system.Newton disk - a disk on which there are seven colored sectors, which, when rapidly rotated, appear white.Newton law - the attractive force between any two bodies is proportional to the product of their masses and inversely proportional to the square of the distance between their centers. Synonym(s): law of gravitationNewton rings - colored rings on thin surfaces.newtonian aberration - the difference in focus or magnification of an image arising because of a difference in the refraction of different wavelengths composing white light. Synonym(s): chromatic aberrationnewtonian constant of gravitation - a universal constant relating the gravitational force, attracting two masses toward each other when they are separated by a distance.newtonian flow - the type of flow characteristic of a newtonian fluid.newtonian fluid - a fluid in which flow and rate of shear are always proportional to the applied stress.newtonian viscosity - the viscosity characteristics of a newtonian fluid.
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