viscosity

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Related to Viscous friction: Viscous Force

viscosity

 [vis-kos´ĭ-te]
resistance to flow; a physical property of a substance that is dependent on the friction of its component molecules as they slide by one another.

vis·cos·i·ty

(vis-kos'i-tē),
In general, the resistance to flow or alteration of shape by any substance as a result of molecular cohesion; most frequently applied to liquids as the resistance of a fluid to flow because of a shearing force.
[L. viscositas, fr. viscosus, viscous]

viscosity

An MRI term for a measure of a fluid’s resistance to deformity by shear or tensile stress, which affects its mobility and therefore its intensity in an image.

viscosity

The tendency of a fluid to resist flow or the quality of resistance to flow; viscosity is measured with a viscometer to assess hyperviscosity syndromes associated with monoclonal gammopathies, rheumatoid arthritis, SLE, hyperfibrinogenemia Ref range 1.4-1.8 relative to water. See Apparent viscosity. Cf Specific gravity.

vis·cos·i·ty

(vis-kos'i-tē)
In general, the resistance to flow or alteration of shape by any substance as a result of molecular cohesion; most frequently applied to liquids as the resistance of a fluid to flow because of a shearing force.
[L. viscositas, fr. viscosus, viscous]

viscosity

  1. the property of stickiness by which substances resist change of shape.
  2. a measure of the ease with which layers of fluid pass each other.

vis·cos·i·ty

(vis-kos'i-tē)
In general, the resistance to flow or alteration of shape by any substance as a result of molecular cohesion.
[L. viscositas, fr. viscosus, viscous]
References in periodicals archive ?
Elastic suspension of the LM has rigidity [k.sub.v] = 153291 N/m, coefficient of viscous friction [b.sub.v] = 44.9 kg/s.
Two typical faults in actuators of UM were considered: fault caused by changing of viscous friction moment and error in the sensor, which measures the position of output shaft of gear.
At low temperature viscous friction is a significant contributor to the total power requirement of the pump.
Simulations performed with viscous friction near to zero revealed no improvement of the response time.
As far as the effective low area is concerned, this is a consequence of the greater viscous friction in the radial flow, which is observed when the clearance becomes narrower, reducing the mass flow rate.
In CP (1), for convenience of writing and analysis, the following notations are accepted: [T.sub.d] = [+ or -] [[beta].sub.C]/[c.sub.12] is time constant due to viscous friction; [T.sub.y] = 1/[[OMEGA].sub.12] is the time constant of elastic vibrations.
However, the behavior of the identified viscous friction coefficient [??]([t.sub.k]), shown in Figure 6(b), may disagree with the actual phenomenon in which the viscous friction is proportional to the velocity and reaches zero at zero angular velocity.
where, v is the relative velocity between the two surfaces, [F.sub.c] is the coulomb friction level, [F.sub.s] is the level of the stiction force, [v.sub.s] is the Stribeck velocity, [[sigma].sub.0] is the stiffness, [[sigma].sub.1] is the viscous damping coefficient, and [[sigma].sub.2] is the viscous friction coefficient.
It is assumed that the following types of faults are possible in the actuators of MM: [d.sub.1]-fault caused by an increase of moment of viscous friction in the link of manipulator; [d.sub.2]-fault caused by an increase of moment of viscous friction in the actuator; [d.sub.3]-fault caused by the change of active resistance of rotor circuit of DC motors (for example, in case of significant changing of temperature).
Parameters of PC servo motor and tacho generator Motor constants Symbol Rated Voltage [U.sub.n] Stream idle [I.sub.0] Permissible maximum current [I.sub.max] Inductance coil [L.sub.a] Winding resistance [R.sub.a] Rated engine speed n Torque constant [K.sub.t] Constant voltage [K.sub.e] Mechanical time constant [T.sub.m] Moment of inertia of the engine J Viscous friction B Motor constants Value Rated Voltage 12 V Stream idle 0.044 A Permissible maximum current 1.5 A Inductance coil 0.0003 H Winding resistance 2.5 [OHM] Rated engine speed 5800 rpm Torque constant 0.0195 Nm/A Constant voltage 0.01957 Vs/rad Mechanical time constant 0.012 s Moment of inertia of the engine 17.6-[10.sup.-7] kg[m.sup.2] Viscous friction 1 x [10.sup.-6] Nms/rad
Viscous friction also creates a force to resist motion, but the effect is proportional to speed.
where [u.sub.A] represents the input voltage, [R.sub.A] is the electric resistance, [i.sub.A] is the armature current, e is the counter-electromotive force, L is the electric inductance, [K.sub.m] motor torque constant, [K.sub.e] ([K.sub.m] = [K.sub.e]) electromotive force constant, [K.sub.d][[omega].sub.m] ([K.sub.d] = b) damping torque given by the loss of magnetic field and viscous friction in the motor's bearings, [M.sub.m] is the motor's torque, [M.sup.r.sub.r] is the resistant torque reduced in the axle of the motor, [I.sup.r] is the moment of inertia of the rotor and [i.sub.total] = [i.sub.reducer][i.sub.transmission].