Poise viscosity

In decreasing order of exactness, methods of defining viscosity include absolute (poise) viscosity kinematic viscosity in centistokes relative viscosity in Saybolt universal seconds (SUS) and SAE numbers. 

The resistance when moving one layer of liquid over another is the basis for the laboratory method of measuring absolute viscosity. Poise viscosity is defined as the force (pounds) per unit of area, in square inches, required to move one parallel surface at a speed of one centimeter-per-second past another parallel surface when the two surfaces are separated by a fluid film one centimeter thick. Figure 40.16. In the metric system, force is expressed in dynes and area in square centimeters. Poise is also the ratio between the shearing stress and the rate of shear of the fluid. 

The unit of viscosity (tj) is called a poise. Viscosity is determined experimentally by measuring the length of time (t) for a certain volume (V) of liquid to run through a capillary tube of radius R and length L under a pressure P, according to the Poiseuille equation... 

Carbon Crucible Tests Temp., °F Observed Viscosity, poises Viscosity (poises) Calculated from Predictive Correlations ... 

Boundary Layer Theory. The Reynolds number for flow-through hollow fibers during our experiments was at most about 0.02 cm (diameter) x 4 cm/sec (velocity) x 1.0 g/cm (density)/ 0.007 poise (viscosity) 11 therefore, a boundary layer theory is needed for laminar flow in tubes. Because of its simplicity, the most attractive available theory is an approximate result of thln-film theory. This theory is restricted to a description of boundary layers that are thin in comparison to the tube radius. Furthermore, the ultrafiltrate velocity, J, must not vary along the tube length (uniform-wall-flux theory). At the centerline or axis of the fiber, the impermeable solute concentration C = C... 

Oldshue (1966), by using the above equation, showed the various bubble sizes required to have various terminal velocities for fluids with a specific gravity of 1.0 and varying viscosities. If air bubbles are to rise from viscous fluids with any appreciable velocity, then they must have a reasonable size. For example in fluid of 10 poise viscosity, bubbles that are less than 0.76 mm in diameter will remain in the system, and only those that are 2.03 mm or larger will enter and pass out with any appreciable velocity. This, of course, causes much more difficulty in a small-scale fermenter than it would in a large-scale one. 

Saltation-1 m diameter particle, 10 poise viscosity Chromosomes ... 

The viscosity of a simple liquid has been explained and defined in Chapter 1. It is the outward evidence of the internal resistance to flow and can be measured in units called poises , or in SI units of pascal-seconds . Both are used in this section of the book instruments currently in use may still be mainly calibrated in poises. Viscosity can be measured by any method involving either the flow of the liquid, or the movement of some object in the liquid. 

Comparative effects of viscous and gravity forces At ordinary waterflood conditions, capillary number is about 10 7. This corresponds to a flow rate of about 1 ft/day for water of one centi-poise viscosity and an oil-water interfacial tension of 30 dyne/cm. The capillary number for 50% reduction of residual saturations in sphere packings is close to 10 (Figure 4), and would require that interfacial tension be reduced to 0.3 dyne/cm for the above flow rate and viscosity. For vertical displacement at very low capillary numbers, the Bond number at which saturation is reduced 50% by buoyancy forces is about 0.08. If the fluid density difference is 0.2, the sphere radius of the packings would be 35... 

The basic definition of viscosity should be considered in terms of equation (8.3). Consider two 1-cm planes 1 cm apart imbedded in a liquid. If it takes 1 dyne of force to move one of the planes 1 cm/s relative to the other in a shearing motion, the liquid has a viscosity of 1 poise. Viscosity is also expressed in pascal-seconds, with IPa-s = 0.1 poise. 

Viscosity. The viscosity of an oil is a measure of its resistance to internal flow and is an indication of its oiliness in the lubrication of surfaces. In the centimeter-gram-second (cgs) system the unit of viscosity is the poise or centipoise (0.01 poise). Viscosity may be defined as the force in dynes required to move a plane of T sq cm area, at... 

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